Abstract
Background:
The good qualities of breastfeeding are well known. The aim of this study was to closely examine the impact of specific maternal, prenatal, obstetric, and early neonatal factors on the success of breastfeeding.
Materials and Methods:
We used data from the Kuopio Birth Cohort study and analyzed 2,521 online questionnaires, which were answered by women 1 year after giving birth. Breastfeeding variables were divided into successful breastfeeding (breastfeeding exclusively with one’s own breast milk ≥4 months or breastfeeding with formula ≥6 months) and poor breastfeeding (breastfeeding exclusively with one’s own milk <4 months and duration of all breastfeeding <6 months) for univariate and multivariable analyses.
Results:
In this study, 97.8% (N = 2,466) reported breastfeeding their newborns for ≥1 postnatal week, and 75.2% (N = 1,896) breastfed newborns for ≥6 months. The rate of breastfeeding for ≥6 months increased from 71.3% to 84.7% between 2013 and 2020. In the multivariable analysis, poor breastfeeding success was associated most significantly with smoking during pregnancy (adjusted odds ratio [aOR] 4.64; 95% confidence interval [CI]: 2.75–7.81), twin pregnancy (aOR 4.13; 95% CI: 2.10–8.15), maternal obesity (body mass index > 35) (aOR 3.27; 95% CI: 2.15–4.99), fear of childbirth (aOR 2.80; 95% CI: 1.89–4.13), and birth during the period of 2013–2014 (aOR 2.94; 95% CI: 2.08–4.14) or 2015–2016 (aOR 2.62; 95% CI: 1.85–3.70). Other significant factors related to poor success were younger maternal age, nonmarried family relationships, passive or quitting smoking before or in the first trimester, any hypertensive disorder during pregnancy, birth by nonelective cesarean, and lowest or highest quartiles of birth weight.
Conclusions:
Mother’s fear of childbirth is strongly associated with the poor breastfeeding success even after controlling for mode of birth.
Keywords: birth, breastfeeding, breast milk, cesarean delivery, childbirth fear, delivery, hypertensive disorders, lactation, maternity infant, preeclampsia, pregnancy
Introduction
Breastfeeding has many positive health benefits for the infant and mother.1,2 Many maternal and social factors may affect the success of breastfeeding after birth, such as age, weight, parity, education, smoking, and breastfeeding support.3,4 Some intrapartum factors and the mode of delivery have also been evaluated in this context. According to earlier studies, women who give birth by cesarean delivery may have decreased milk production due to decreased oxytocin secretion or maternal stress.3 Furthermore, longer bed rest after operation may lead to worse ability to nurse newborns, leading to greater use of bottle feeding with formula, reduced lactation stimulus, and reduced sucking capacity of the newborn.5,6 Some central analgesics that are often used in cesarean delivery might also reduce the level of endogenous maternal endorphins and thereby disturb at newborn’s sucking behavior.7
The possible effects of other modes of deliveries or different types of cesareans have not been evaluated sufficiently. However, physiological and mental distress is higher in women who have obstetric interventions or prolonged labor than women who have natural or successful vaginal delivery.8 In addition, women who fear childbirth frequently request cesarean delivery and are more likely to have impaired resilience and social support during the peripartum period.9 However, breastfeeding women are less likely to develop postpartum depression, and longer breastfeeding duration may be protective for mental health in a subset of hormone-sensitive women by attenuating the neuroendocrine response and promoting better interaction between the mother and infant.10–13
The World Health Organization (WHO) recommends early initiation of breastfeeding within 1 hour of birth and exclusive breastfeeding for the first six months of life. Complementary foods may be introduced at 6 months together with continued breastfeeding even up to 2 years of age or beyond.2 The WHO and the United Nations Children’s Fund have launched the Baby-Friendly Hospital Initiative to encourage and support mothers to successfully breastfeed around the world. It involves 10 steps to successful breastfeeding, including skin-to-skin contact immediately after birth, breastfeeding within the first hour of life, breastfeeding on demand (i.e., breastfeeding as often as needed at any time of the day), and not giving babies additional food or drink unless medically necessary.14 In Nordic countries, full breastfeeding is recommended until the baby is 4–6 months old, followed by partial breastfeeding with solid foods until at least 12 months of age.15
The purpose of the present study was to closely examine the specific maternal, prenatal, obstetric, and early neonatal factors and their association with the success of breastfeeding. The results could be used to better identify mothers who could potentially have more challenges with breastfeeding after birth and might benefit more from enhanced breastfeeding education during pregnancy and after delivery.
Materials and Methods
This study was part of the Kuopio Birth Cohort (KuBiCo) study in Finland (www.kubico.fi). KuBiCo started in 2012 with the aim of resolving issues related to pregnancy and other early-life factors in terms of the health of mothers and their children. KuBiCo is a joint study with the University of Eastern Finland, Kuopio University Hospital (KUH), and the National Institute for Health and Welfare. The study invited all women who are going to give a birth at KUH to participate in online questionnaires and biological samples.16 During the years 2012–2022, the participation rate was 29–44% of all parturients who delivered in KUH.
The present study included 2,521 women who had answered the KuBiCo questionnaire (including breastfeeding questions) ∼1 year after giving birth in 2013–2020. The questions of interest were focused on the duration and success of breastfeeding and the use of infant formula. Breastfeeding variables were divided into three categories: (1) feeding exclusively with one’s own breast milk for 4 months or more (Nordic recommendations: 4–6 months), (2) duration of any breastfeeding of 6 months or more, and (3) poor breastfeeding success defined as breastfeeding exclusively with one’s own milk <4 months and duration of any breastfeeding <6 months.
Maternal demographics as well as prenatal, obstetric, and early neonatal data were mainly gathered from the KUH Birth Register. These variables included birth year, maternal age, parity, weight, body mass index (BMI, kilogram per square meter), smoking, possible infertility treatment before current pregnancy, family relationship, education (years), gestational weight gain (kilogram) and gestational age at birth (weeks), duration of labor (hours) for vaginal deliveries, mode of birth (spontaneous vaginal, vacuum-assisted vaginal, elective cesarean, and nonelective cesarean), amount of blood loss at delivery (milliliter) for both vaginal and cesarean deliveries, number of fetuses (twins), sex, birth weight (gram), Apgar scores at 5 minutes, need for neonatal intensive care after birth, duration of hospital stay after birth (days), and specific International Classification of Diseases, 10th revision (ICD-10) codes for pre-pregnancy and pregnancy diseases (such as pregestational diabetes mellitus or hypertension, gestational diabetes, preeclampsia or other hypertensive disorder during pregnancy, birth fear) and indications for cesarean delivery. ICD-10 codes were given to women during ongoing pregnancy and immediately after delivery by the attending physician.
Pregestational diabetes mellitus was defined from the hospital and birth registers by ICD-10 codes such as O24.0–O24.3 or E10–E11 and hypertension with codes of I11–15 or O10–O11. Gestational diabetes mellitus was defined similarly with codes O24.4, and further preeclampsia or other gestational hypertension was defined with codes O13–O16. Fear of childbirth was recorded as ICD-10 code O99.80 either during pregnancy or during delivery. Major indications for cesarean delivery were included as they were reported in operative reports and were divided into eight different groups: (1) fetal distress (defined as ICD-10 codes O68–O69), (2) prolonged labor or failed induction (O61–O62.2 or O63), (3) breech presentation (O64.1), (4) previous cesarean delivery (O34.2), (5) fetal malpresentation other than breech (O64.0, O64.2–O64.9), (6) fear of childbirth (O99.80), (7) fetal size (O36.5 or O36.6), and (8) other indications not included in the earlier definitions. Some women had more than one indication for operation.
Birth fear is routinely screened by electric questionnaire during pregnancy at outpatient maternity clinics in health centers by attending nurses. Women with possible birth fear are sent to special “birth fear” policlinics in KUH’s maternal outpatient policlinics. The treatment offered depends on the severity of birth fear but usually comprises at least two to three different appointments with a specialized doctor or nurse. In KUH, nearly 60–70% of women with birth fear have vaginal deliveries.
Participants in the KuBiCo project had voluntarily responded to the questionnaires, were aware of their involvement in the study, and gave written informed consent before participation. The Research Ethics Committee of Hospital District of Central Finland has approved the KuBiCo plan (11/2011).
All the statistical analyses were performed with IBM SPSS Statistics (Version 27). Most continuous variables were grouped as quartiles (maternal age, weight in the first trimester, gestational weight gain, birth weight, and duration of labor). Blood losses after delivery were divided by 90th-percentile cutoffs or with other clinically significant definitions (BMI, Apgar scores, gestational age at birth, neonatal hospital stay after delivery). Nominal variables were evaluated with Pearson’s chi-squared test, and linear variables were evaluated by Pearson’s correlation coefficient (r) analysis. Logistic regression analysis was used to investigate multivariable simultaneous relationships between poor breastfeeding success and adjusted effects of various predictors or confounders.
A priori, predictors chosen for the logistic regression analysis were selected as variables that were significantly associated (p < 0.05) with breastfeeding in the univariate analysis (Tables 2 and 3). However, many significant maternal and neonatal variables were strongly correlated with each other, such as (1) maternal age and parity, (2) maternal age and schooling years, (3) duration of gestation at birth and birth weight, and (4) Apgar scores, duration of hospital stay, and need for neonatal intensive care treatment. To avoid collinearity in the multivariable analysis, variables with strongest association in univariate analysis with poor breastfeeding success were included in the multivariable logistic analysis, and the results were described by adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Variables were entered simultaneously in the multivariable analysis, and only those with significant association are shown in the results (Table 4). Results were considered significant with p-values <0.05.
Table 2.
Maternal Factors in Relation to Successful Breastfeeding Among 2,521 Women During the First Year After Childbirth
| Variables | Total N (%) | Any breastfeeding ≥6 months | p-Value | Exclusive breastfeeding ≥4 months | p-Value | Poor breastfeeding | p-Value |
|---|---|---|---|---|---|---|---|
| Age, years | |||||||
| ≤28 | 782 (31.0) | 543 (69.4) | 0.0001 | 338 (43.2) | 0.174 | 226 (28.9) | 0.0001 |
| 29–31 | 609 (24.2) | 485 (79.6) | 289 (47.5) | 114 (18.7) | |||
| 32–34 | 552 (21.9) | 428 (77.5) | 267 (48.4) | 117 (21.2) | |||
| ≥35 | 578 (22.9) | 440 (76.1) | 254 (43.9) | 129 (22.3) | |||
| Weight in first trimester, kg | |||||||
| ≤59 | 701 (27.8) | 539 (76.9) | 0.0001 | 327 (46.6) | 0.003 | 153 (21.8) | 0.0001 |
| 60–65 | 618 (24.5) | 493 (79.8) | 306 (49.5) | 115 (18.6) | |||
| 66–75 | 594 (23.6) | 463 (77.9) | 276 (46.5) | 121 (20.4) | |||
| ≥76 | 608 (24.1) | 401 (66.0) | 239 (39.3) | 197 (32.4) | |||
| Body mass index first trimester, kg/m2 | |||||||
| ≤25 | 1,563 (62.0) | 1,243 (79.5) | 0.0001 | 759 (48.6) | 0.0001 | 300 (19.2) | 0.0001 |
| >25–30 | 574 (22.8) | 422 (73.5) | 261 (45.5) | 140 (24.4) | |||
| >30–35 | 266 (10.6) | 171 (64.3) | 99 (37.2) | 92 (34.6) | |||
| >35 | 118 (4.7) | 60 (50.8) | 29 (24.6) | 54 (45.8) | |||
| Parity | |||||||
| Nulliparous | 1,352 (53.6) | 985 (72.9) | 0.011 | 562 (41.6) | 0.0001 | 346 (25.6) | 0.009 |
| Primiparous | 726 (28.8) | 570 (78.5) | 363 (50.0) | 145 (20.0) | |||
| Multiparous | 443 (17.6) | 341 (77.0) | 223 (50.3) | 95 (21.4) | |||
| Smoking during pregnancy | |||||||
| No | 2,031 (80.6) | 1,612 (79.4) | 0.0001 | 978 (48.2) | 0.0001 | 392 (19.3) | 0.0001 |
| Passive smoking, quitted before pregnancy or during first trimester | 417 (16.5) | 259 (62.1) | 156 (37.4) | 151 (36.2) | |||
| Yes, smoking throughout pregnancy or quitted after first trimester | 73 (2.9) | 25 (34.3) | 14 (19.2) | 43 (58.9) | |||
| Family relationship | |||||||
| Married | 1,404 (55.7) | 1,116 (79.5) | 0.0001 | 669 (47.6) | 0.002 | 267 (19.0) | 0.0001 |
| Cohabitation or other partnership | 1,014 (40.2) | 725 (71.5) | 447 (44.1) | 276 (27.2) | |||
| Single | 103 (4.1) | 55 (53.4) | 32 (31.1) | 43 (41.7) | |||
| Schooling, yearsa | |||||||
| ≤15 | 651 (34.4) | 440 (67.6) | 0.0001 | 281 (43.2) | 0.054 | 197 (30.3) | 0.0001 |
| 16 | 391 (20.7) | 308 (78.8) | 191 (48.8) | 78 (19.9) | |||
| 17–18 | 492 (26.0) | 420 (85.4) | 243 (49.4) | 69 (14.0) | |||
| ≥19 | 359 (19.0) | 297 (82.7) | 183 (51.0) | 55 (15.3) | |||
| Any infertility treatment before onset of pregnancy | 197 (7.8) | 144 (73.1) | 0.475 | 83 (42.1) | 0.317 | 49 (24.9) | 0.573 |
| Pregestational diabetes mellitus | 32 (1.3) | 25 (78.1) | 0.701 | 12 (37.5) | 0.358 | 7 (21.9) | 0.854 |
| Pregestational hypertensive disorderb | 27 (1.1) | 14 (51.9) | 0.005 | 6 (22.2) | 0.014 | 13 (48.1) | 0.002 |
| Gestational diabetes mellitus | 478 (19.0) | 350 (73.2) | 0.264 | 212 (44.4) | 0.563 | 123 (25.7) | 0.153 |
| Preeclampsia or other gestational hypertensive disordersc | 144 (5.7) | 90 (62.5) | 0.0001 | 50 (34.7) | 0.007 | 52 (36.1) | 0.0001 |
| Any hypertensive disorder during pregnancy or delivery | 164 (6.5) | 99 (60.4) | 0.0001 | 56 (34.1) | 0.002 | 63 (38.4) | 0.0001 |
| Fear of childbirth during pregnancy or delivery | 145 (5.8) | 83 (57.2) | 0.0001 | 54 (37.2) | 0.039 | 59 (40.7) | 0.0001 |
| Birth year | |||||||
| 2013–2014 | 773 (30.7) | 551 (71.3) | 0.0001 | 332 (42.9) | 0.292 | 211 (27.3) | 0.0001 |
| 2015–2016 | 703 (27.9) | 494 (70.3) | 320 (45.5) | 192 (27.3) | |||
| 2017–2018 | 640 (25.4) | 508 (79.4) | 306 (47.8) | 123 (19.2) | |||
| 2019–2020 | 405 (16.1) | 343 (84.7) | 190 (46.9) | 60 (14.8) | |||
| Total | 2,521 (100) | 1,896 (75.2) | 1,148 (45.5) | 586 (23.2) |
Poor breastfeeding defined as breastfeeding exclusively with one’s own milk <4 months and duration of any breastfeeding <6 months.
Data available in 1,893 women.
Including ICD-10 codes I10, O10–O11.
Including ICD-10 codes O13–016. p-Values are estimated by Pearson’s Chi-squared test.
ICD-10, International Classification of Diseases, 10th revision.
Table 3.
Intrapartum and Early Neonatal Factors in Relation to Successful Breastfeeding Among 2,521 Women During the First Year After Childbirth
| Variables | Total N (%) | Any breastfeeding ≥6 months | p-Value | Exclusive breastfeeding ≥4 months | p-Value | Poor breastfeeding | p-Value |
|---|---|---|---|---|---|---|---|
| Gestational age at birth, weeks | |||||||
| ≤36 | 129 (5.1) | 88 (68.2) | 0.008 | 49 (38.0) | 0.037 | 38 (29.5) | 0.004 |
| 37–38 | 431 (17.1) | 303 (70.3) | 181 (42.0) | 124 (28.8) | |||
| 39 | 723 (28.7) | 558 (77.2) | 323 (44.7) | 158 (21.9) | |||
| 40 | 711 (28.2) | 555 (78.1) | 353 (49.6) | 141 (19.8) | |||
| ≥41 | 527 (20.9) | 392 (74.4) | 242 (45.9) | 125 (23.7) | |||
| Maternal weight gain during pregnancy, kga | |||||||
| -10 | 597 (25.7) | 433 (72.5) | 0.060 | 247 (41.4) | 0.144 | 153 (25.6) | 0.131 |
| 11–14 | 759 (32.7) | 595 (78.4) | 360 (47.4) | 157 (20.7) | |||
| 15–17 | 470 (20.2) | 355 (75.5) | 215 (45.7) | 105 (22.3) | |||
| ≥18 | 495 (21.3) | 363 (73.3) | 230 (46.5) | 123 (24.8) | |||
| Duration of labor, hoursb | |||||||
| ≤ 5 | 500 (23.8) | 406 (81.2) | 0.041 | 246 (49.2) | 0.092 | 88 (17.6) | 0.069 |
| 5–8 | 505 (24.0) | 401 (79.4) | 254 (50.3) | 98 (19.4) | |||
| 8–13 | 578 (27.5) | 431 (74.6) | 275 (47.6) | 137 (23.7) | |||
| >13 | 519 (24.7) | 396 (76.3) | 223 (43.0) | 114 (22.0) | |||
| Twin pregnancy | 42 (1.7) | 17 (40.5) | 0.0001 | 9 (21.4) | 0.002 | 24 (57.1) | 0.0001 |
| Mode of delivery | |||||||
| Spontaneous vaginal delivery | 1,982 (78.6) | 1,536 (77.5) | 0.0001 | 937 (47.3) | 0.004 | 419 (21.1) | 0.0001 |
| Vacuum assisted vaginal delivery | 211 (8.4) | 151 (71.6) | 90 (42.7) | 55 (26.1) | |||
| Elective cesarean delivery | 122 (4.8) | 80 (65.6) | 48 (39.3) | 39 (32.0) | |||
| Nonelective cesarean delivery | 206 (8.2) | 129 (62.6) | 73 (35.4) | 73 (35.4) | |||
| Indications for cesarean delivery (N = 328) | |||||||
| Fetal distress | 86 (26.2) | 53 (61.6) | 0.639 | 35 (40.7) | 0.394 | 30 (34.9) | 0.867 |
| Prolonged labor or failed induction | 83 (25.3) | 50 (60.2) | 0.446 | 28 (33.7) | 0.491 | 30 (36.1) | 0.657 |
| Breech presentation | 81 (22.0) | 55 (67.9) | 0.367 | 29 (35.8) | 0.815 | 25 (30.9) | 0.473 |
| Previous cesarean delivery | 65 (19.8) | 41 (63.1) | 0.904 | 29 (44.6) | 0.149 | 22 (33.8) | 0.955 |
| Fetal malpresentation other than breech | 45 (13.7) | 23 (51.1) | 0.058 | 11 (24.4) | 0.062 | 21 (46.7) | 0.057 |
| Fear of childbirth | 43 (13.1) | 19 (44.2) | 0.004 | 11 (25.6) | 0.099 | 22 (51.2) | 0.012 |
| Fetal size | 31 (9.5) | 19 (61.3) | 0.768 | 8 (25.8) | 0.179 | 11 (35.5) | 0.869 |
| Other indications | 56 (17.1) | 38 (67.9) | 0.951 | 36 (64.3) | 0.907 | 17 (30.4) | 0.589 |
| Blood loss after vaginal delivery ≥800 mLc | 265 (12.2) | 213 (80.4) | 0.415 | 119 (44.9) | 0.467 | 50 (18.9) | 0.295 |
| Blood loss after cesarean delivery ≥1,400 mLd | 38 (11.9) | 28 (73.7) | 0.192 | 17 (44.7) | 0.321 | 9 (23.7) | 0.166 |
| Newborn, male | 1,292 (51.2) | 957 (74.1) | 0.175 | 573 (44.3) | 0.220 | 317 (24.5) | 0.116 |
| Birth weight, g | |||||||
| ≤3,180 | 636 (25.2) | 433 (68.1) | 0.0001 | 251 (39.5) | 0.0001 | 194 (30.5) | 0.0001 |
| 3,181–3,510 | 636 (25.2) | 494 (77.7) | 259 (46.4) | 133 (20.9) | |||
| 3,511–3,830 | 633 (25.1) | 507 (80.1) | 323 (51.0) | 111 (17.5) | |||
| ≥3,831 | 616 (24.4) | 462 (75.0) | 279 (45.3) | 148 (24.0) | |||
| Apgar scores, 5 minutes | |||||||
| ≤7 | 84 (3.3) | 57 (67.9) | 0.0001 | 32 (38.1) | 0.002 | 26 (31.0) | 0.003 |
| 8 | 115 (4.6) | 76 (66.1) | 44 (38.3) | 39 (33.9) | |||
| 9 | 1,947 (77.2) | 1,463 (75.1) | 870 (44.7) | 450 (23.1) | |||
| 10 | 375 (14.9) | 300 (80.0) | 202 (53.9) | 71 (18.9) | |||
| Neonatal hospital stay after birth, days | |||||||
| 0–1 | 182 (7.2) | 136 (74.7) | 0.0001 | 89 (48.9) | 0.016 | 43 (23.6) | 0.0001 |
| 2 | 1,172 (46.5) | 934 (79.7) | 565 (48.2) | 220 (18.8) | |||
| 3 | 724 (28.7) | 540 (74.6) | 316 (43.6) | 176 (24.3) | |||
| ≥4 | 443 (17.6) | 286 (64.6) | 178 (40.2) | 147 (33.2) | |||
| Need for neonatal intensive care after birth | 282 (11.2) | 189 (67.0) | 0.0001 | 119 (42.2) | 0.232 | 89 (31.6) | 0.0001 |
| Total | 2,521 (100) | 1,896 (75.2) | 1,148 (45.5) | 586 (23.2) |
Poor breastfeeding defined as breastfeeding exclusively with one’s own milk <4 months and duration of any breastfeeding <6 months. Data available.
2,321.
2,102.
2,179 and in.
318 women. p-Values are estimated by Pearson’s Chi-squared test.
Table 4.
Multivariable Analysis of Significant Clinical Risk Factors in Relation to Poor Breastfeeding Success Among 2,521 Women During the First Year After Childbirth
| Poor breastfeeding | ||||
|---|---|---|---|---|
| N (%) | OR (95% CI) | aOR (95% CI) | p-Value | |
| Age, years | ||||
| ≤28 | 226 (28.9) | 1.77 (1.37–2.28) | 1.61 (1.22–2.13) | 0.005 |
| 29–31 | 114 (18.7) | 1 | 1 | |
| 32–34 | 117 (21.2) | 1.17 (0.88–1.56) | 1.23 (0.91–1.68) | |
| ≥35 | 129 (22.3) | 1.25 (0.94–1.66) | 1.15 (0.85–1.56) | |
| Body mass index first trimester, kg/m2 | ||||
| ≤25 | 300 (19.2) | 1 | 1 | 0.0001 |
| >25–30 | 140 (24.4) | 1.36 (1.08–1.71) | 1.40 (1.09–1.78) | |
| >30–35 | 92 (34.6) | 2.23 (1.68–2.95) | 2.26 (1.66–3.08) | |
| >35 | 54 (45.8) | 3.55 (2.42–5.21) | 3.27 (2.15–4.99) | |
| Smoking during pregnancy | ||||
| No | 392 (19.3) | 1 | 1 | 0.0001 |
| Passive smoking or quitted before pregnancy or during first trimester | 151 (36.2) | 2.37 (1.89–2.98) | 1.98 (1.54–2.53) | |
| Yes, smoking throughout pregnancy or quitted after first trimester | 43 (58.9) | 5.99 (3.72–9.68) | 4.64 (2.75–7.81) | |
| Family relationship | ||||
| Married | 267 (19.0) | 1 | 1 | 0.0001 |
| Cohabitation or other partnership | 276 (27.2) | 1.59 (1.31–1.93) | 1.41 (1.14–1.74) | |
| Single | 43 (41.7) | 3.05 (2.02–4.62) | 2.36 (1.49–3.74) | |
| Any hypertensive disorder during pregnancy or delivery | 63 (38.4) | 2.19 (1.57–3.04) | 1.70 (1.18–2.46) | 0.005 |
| Fear of childbirth during pregnancy or delivery | 59 (40.7) | 2.41 (1.70–3.40) | 2.80 (1.89–4.13) | 0.0001 |
| Birth year | ||||
| 2013–2014 | 211 (27.3) | 2.16 (1.57–2.96) | 2.94 (2.08–4.14) | 0.0001 |
| 2015–2016 | 192 (27.3) | 2.16 (1.57–2.98) | 2.62 (1.85–3.70) | |
| 2017–2018 | 123 (19.2) | 1.37 (0.98–1.92) | 1.42 (0.99–2.04) | |
| 2019–2020 | 60 (14.8) | 1 | 1 | |
| Twin pregnancy | 25 (59.5) | 4.55 (2.45–8.44) | 4.13 (2.10–8.15) | 0.0001 |
| Mode of delivery | ||||
| Spontaneous vaginal delivery | 419 (21.1) | 1 | 1 | 0.034 |
| Vacuum assisted vaginal delivery | 55 (26.1) | 1.32 (0.95–1.82) | 1.21 (0.85–1.71) | |
| Elective cesarean delivery | 39 (32.0) | 1.75 (1.18–2.60) | 1.22 (0.78–1.91) | |
| Nonelective cesarean delivery | 73 (35.4) | 2.05 (1.51–2.78) | 1.62 (1.16–2.27) | |
| Birth weight, g | ||||
| ≤3,180 | 194 (30.5) | 2.06 (1.58–2.69) | 1.88 (1.40–2.51) | 0.0001 |
| 3,181–3,510 | 133 (20.9) | 1.24 (0.94–1.65) | 1.25 (0.93–1.68) | |
| 3,511–3,830 | 111 (17.5) | 1 | 1 | |
| ≥3,831 | 148 (24.0) | 1.49 (1.13–1.96) | 1.46 (1.18–2.46) | |
Poor breastfeeding defined as breastfeeding exclusively with one’s own milk <4 months and duration of any breastfeeding <6 months. All shown variables with Apgar scores at 5 minutes were entered simultaneously in adjusted model. Information of schooling years was missing in 628 women. Maternal age and schooling years correlated strongly (r = 0.302). If schooling years were included in the model (N = 1,893), the significance of maternal age was lost. Apgar scores at 5 minutes were not significant in the multivariable analysis and not reported in the table.
aOR, adjusted odds ratio; CI, confidence interval; OR, odds ratio.
Results
Among 2,521 women, 97.8% (N = 2,466) reported breastfeeding their newborns within the first postnatal week and beyond, and 75.2% (N = 1,896) breastfed newborns for ≥6 months (Table 1). Furthermore, 45.5% (N = 1,148) of women reported breastfeeding exclusively with their own milk for ≥4 months. In 23.2% (N = 586) of cases, mothers breastfed with poor success (duration of <6 months and exclusively with their own milk <4 months). The percentages of mothers with successful breastfeeding for ≥6 months increased from 71.3% to 84.7% from the years 2013–2014 to 2019–2020 (Table 2), while the rate of poor breastfeeding decreased from 27.3% to 14.8%. Women with poorer breastfeeding success tended to be younger, nulliparous, overweight or obese, unmarried, current or previous smokers, less educated, fearful of childbirth, or hypertensive during pregnancy (Table 2).
Table 1.
Breastfeeding During the First Year After Childbirth Among 2,521 Women
| Outcomes | N (%) |
|---|---|
| Duration of any breastfeeding | |
| ≥1 week | 2,466 (97.8) |
| ≥4 months | 2,074 (82.3) |
| ≥6 months | 1,896 (75.2) |
| ≥8 months | 1,710 (67.8) |
| Exclusively one’s own milk | |
| ≥1 month | 2,046 (81.2) |
| ≥4 months | 1,148 (45.5) |
| ≥6 months | 123 (4.9) |
| First use of infant formula | |
| ≤1 week | 839 (33.3) |
| ≤1 month | 1,004 (39.8) |
| 1–3 months | 300 (11.9) |
| ≥4 months | 577 (22.9) |
| Not used | 640 (25.4) |
| Total | 2,521 (100) |
Table 3 describes intrapartum and early neonatal factors in the univariate analysis in relation to successful breastfeeding. Successful breastfeeding was most frequent among women with spontaneous vaginal delivery at 40 gestational weeks with gestational weight gain of 11–14 kg. The most significant variable for poor breastfeeding was twin pregnancy; 40.5% of twin mothers reported breastfeeding for ≥6 months, and 21.4% of them breastfed exclusively for ≥4 months. Mothers who gave birth by operative delivery (either by cesarean or vacuum-assisted vaginal delivery) breastfed significantly less than mothers who had spontaneous vaginal delivery.
Among women with cesarean deliveries, maternal fear of childbirth as an indication for operation was strongly associated with poor breastfeeding success. However, 102 out of 145 (70.3%) women with birth fear had vaginal delivery. Among neonates, the best breastfeeding success was reported among newborns with weight in the 50th–75th percentiles, 5-minute Apgar scores of 10, and 2-day hospital stays after birth. The duration of labor was weakly associated with the breastfeeding success, but after controlling for parity, this association was lost. Maternal blood loss after delivery and neonatal sex was not associated with the success of breastfeeding (Table 3).
Maternal parity and age were strongly correlated with each other (r = 0.358) and were both significantly associated with breastfeeding success in the univariate analysis (Table 2). However, maternal age was a stronger predictor and was thus selected for the multivariable model. Similarly, there were strongly correlations between maternal BMI and weight (r = 0.934) (Table 2); between duration of gestation at birth and birth weight (r = 0.585); and between Apgar scores at 5 minutes, duration of hospital stay, and need for intensive care after birth (r = −0.336, r = −0.197 and r = 0.333). After the avoidance of collinearity, only BMI, birth weight, and Apgar scores at 5 minutes were included in the multivariable model (Table 4).
The results of the multivariable analysis of risk factors in relation to poor breastfeeding success are presented in Table 4. The strongest adjusted predictors of poor success were smoking during pregnancy (aOR 4.64; 95% CI: 2.75–7.81), twin pregnancy (aOR 4.13; 95% CI: 2.10–8.15), maternal obesity (BMI > 35) (aOR 3.27; 95% CI: 2.15–4.99), fear of childbirth (aOR 2.80; 95% CI: 1.89–4.13), and birth during the period of 2013–2014 (aOR 2.94; 95% CI: 2.08–4.14) or 2015–2016 (aOR 2.62; 95% CI: 1.85–3.70). Other statistically significant factors related to poor success were younger maternal age, single status, passive smoking or quitting smoking before pregnancy or in first trimester, any hypertensive disorder during pregnancy, birth by nonelective cesarean, and lowest or highest quartiles of birth weight.
Discussion
Our results confirm that in Finland, mothers breastfeed very well in general. More than 75% of mothers breastfed for at least 6 months, and 45% of mothers breastfed exclusively for 4 months or more. These percentages are some of the best among developed countries besides other Nordic countries and Japan17,18 and are well in line with a recent report from the Finnish Institute for Health and Welfare.19 We also found that the proportion of mothers who breastfed for ≥6 months increased more than 13% between 2013 and 2020. This is likely due to increased awareness of the benefits of breastfeeding, breastfeeding education among health care personnel, and our intense aim to receive baby-friendly hospital accreditation.
As a novel finding, we found that the mother’s fear of childbirth was associated with the poor breastfeeding success even after controlling for the mode of birth. Fear of childbirth increased the risk of poor breastfeeding success by nearly threefold. Since fear of childbirth has been related to postpartum depression, especially in women without history of depression,20 it is possible that some of the poor success in our study is explained by maternal depression. Maternal depression and other mental health disorders such as anxiety and childbirth trauma have been consistently associated with poorer breastfeeding outcomes.21 For some primi- or multiparous women, fear of childbirth has also associated with a previous negative birth experience that is not resolved solely by the elective delivery.22,23 However, maternal parity was not related to the birth fear (5.1% vs. 6.9% vs. 5.9%), and multiparity has been positively associated with the continued breastfeeding also in other studies.24 Furthermore, engaging in and success with breastfeeding may help to ameliorate and ease mental symptoms and strengthen self-efficacy,21,25 and thus, the value of breastfeeding support and its possible therapeutic property should be evaluated further.
The poorest breastfeeding result was related to smoking during pregnancy, twin pregnancy, and maternal obesity in line with earlier reports.3,4,26,27 Low birth weight and prematurity, as well as a lack of breastfeeding support, have predicted breastfeeding cessation earlier among twins.26,28,29 Other significant factors that contributed to unsuccessful breastfeeding were hypertensive disorders of the mother, young age, single or unmarried status, lower or higher birth weight, and nonelective cesarean birth. Successful breastfeeding involves both controllable and uncontrollable factors. For example, more breastfeeding education and timely exclusive prenatal support should be given for mothers at risk who are young and fearful of childbirth, but in cases of twin pregnancy or hungry macrosomic neonates, challenges of breastfeeding may be different than in cases of singleton or normal-weight newborns.
Some earlier studies have shown a similar connection between hypertensive disorders during pregnancy and breastfeeding.30,31 Preeclampsia, gestational hypertension, and pregestational hypertensive disease all together reduced breastfeeding success by almost twofold. In a Canadian study, Horsley et al. showed that the intention to breastfeed and the initiation of breastfeeding were similar between women with and without hypertension, but hypertensive women more often reported insufficient milk supply and were less likely to breastfeed for at least 4 months postpartum.30 Hypertensive disorders and severe preeclampsia also increase the risk of prematurity, birth by cesarean, and thus also poor breastfeeding.31 Earlier sufficient breastfeeding has been associated with lower risk of preeclampsia and hypertensive disorders and a possible reduction in the risk of cardiovascular diseases later in life.31,32 Thus, breastfeeding should receive more attention overall for the prevention of cardiovascular diseases.
Regarding other maternal factors, the youngest women breastfed less than middle-aged mothers, and obese and overweight women had more than 1.4–3.3 times higher risk of poorer breastfeeding than normal-weight and lean mothers. Women with fear of childbirth were significantly more often also overweight and obese (BMI ≤25, >25–30, >30–35, and >35; 5.1%, 5.6%, 7.9%, and 11.0%; data not shown). However, both BMI and fear of childbirth were independently associated with poor breastfeeding results in multivariable analysis. Breastfeeding has also beneficial effects on the mother in postpartum recovery and weight retention.33,34 Breastfeeding was less successful with infants with weight in the highest or lowest quartiles. Both low-weight premature newborns and high-weight newborns may be too tired to breastfeed at first. The need for milk at the beginning of life is also high, which can be problematic if breastfeeding has not yet started properly, and infant formula is needed. Other neonatal factors lost their significance in the multivariable analysis, such as gestational age at birth, need for intensive care, and Apgar scores.
We also showed in univariate analysis that longer duration of labor was weakly associated with poorer breastfeeding. Those who gave birth for more than 13 hours (highest quartile) were less likely to breastfeed for ≥6 months and exclusively for ≥4 months compared with mothers whose labor lasted for <5 hours (lowest quartile), but this association was explained with maternal parity. Only nonelective cesarean delivery was associated weakly with the increased risk of poor breastfeeding, and in contrast to previous studies, elective cesarean lost its significance in the adjusted analysis.5,35 However, the amount of blood loss in childbirth was not associated with success of breastfeeding.
A strength of our research is the large prospectively collected data of mother–child pairs from the KuBiCo study with abundant information on confounders. All participants delivered in KUH with a neonatal hospital stay after birth usually varying between 2 and 3 days, including routine breastfeeding guidance given by educated midwives in the postpartum ward. Breastfeeding data were collected using standard questionnaires at ∼1 year after birth. Thus, it is possible that recall bias may have hampered the collection of exact information about the duration of breastfeeding. The study population is representative of Finnish parturients in general,19 although women with first-time births were overrepresented, and primi- and multiparous women were underrepresented. It is possible that the observed associations between fear of childbirth and poorer breastfeeding success are partly explained by maternal mental disorders or other unmeasured confounding factors, although this study adjusted for many relevant factors in the analyses.
Conclusions
Breastfeeding can be significantly influenced by good breastfeeding support and health education. This study reveals a new finding that fear of childbirth, besides smoking, twin pregnancy, maternal overweight and obesity, and hypertensive disorders during pregnancy, had the most negative effect on breastfeeding success.
Authors’ Contributions
M.V.: Software, writing—original draft, and writing—review and editing. A.K.: Conceptualization and writing—review and editing. K.B.: Investigation, conceptualization, methodology, resources, and writing—review and editing. S.H.: Investigation, conceptualization, resources, and writing—review and editing. L.K.-N.: Conceptualization, methodology, software, formal analysis, resources, data curation, and supervision.
Disclosure Statement
No competing financial interests exist.
Funding Information
This work was supported by the Research Committee of the Kuopio University Hospital Catchment Area for the State Research Funding. The author acknowledges the Research Committee of the Kuopio University Hospital Catchment Area for the State Research Funding (project 5302475, Kuopio, Finland).
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