Table 1. Characteristics of included cohort studies.
| Serial No. | Study ID | Participants | Intervention | Outcomes |
|---|---|---|---|---|
| 1 |
Boulot (2003) France [45] |
PCC: 175 women with (DM-I and DM-II) NO-PCC: 260 women with (DM-I and DM-II) |
PCC included: • Educational delivered by health care of professionals, • Assessment of diabetes complications, • Advice regarding blood glucose optimization, • Dietary modification, • Self-monitoring of blood glucose levels, and insulin therapy. |
PCC: Perinatal mortality: (3/175) Congenital malformations: (2/175) NO-PCC: Perinatal mortality: (16/260) Congenital malformations: (16/260) |
| 2 |
Cousins (1991) USA[37] |
PCC: 27 women with (DM-I and DM-II) NO-PCC: 347 women with (DM-I and DM-II) received care after conception |
PCC included: • A multidisciplinary team approach to care (physicians, Diabetes educators, dietitians and social workers), • Comprehensive education, • Active self- management (e.g. self-glucose monitoring, home testing for ketone- urea, insulin injection techniques), • Routine maternal care elements and laboratory tests, • History and physical examination. |
PCC: Congenital malformations: (0/27) NO-PCC: Congenital malformations: (23/347) |
| 3 | Damm (1989) Denmark[36] |
PCC: 197 women with (DM-I) NO-PCC: 61 women with (DM-I) |
PCC included: • Optimization of diabetic control at the time of conception and nidation and during the first trimester, • Pregnancy planning and contraceptive guidance. |
PCC: First trimester HbA1c: 7.1 ± SD 1.2 (N = 64) Congenital malformations: (2/197) NO-PCC: First trimester HbA1c: 7.3 ± SD 1.5 (N = 21) Congenital malformations: (5/61) |
| 4 |
Dicker (1988) Israel[55] |
PCC: 59 women with (DM-I) NO-PCC: 35 women with (DM-I) |
PCC included: • Insulin and dietary glycemic control, • Advice on contraception, • Screening for diabetes complications. |
PCC: xFirst trimester HbA1c: 7.39 ± SD 0.33 (N = 59) Miscarriage: (5/59) NO-PCC: xFirst trimester HbA1c: 10.49 ± SD 0.48 (N = 35) Miscarriage: (10/35) |
| 5 |
Egan (2016) Ireland [50] |
PCC: 149 women with (DM-I and DM-II) NO-PCC: 265 women with (DM-I and DM-II) |
PCC included: • Patient education, • Full medication review, • Assessment and treatment of diabetes complications and thyroid status. • Folic acid supplement, • Intensive glucose monitoring with a target HbA1c of less than 6.1%, • Dietary advice and Pregnancy planning. |
PCC: First trimester HbA1c: 6.8 ± SD 1.2 (N = 149) CS delivery: (85/149) Congenital malformations: (1/149) Miscarriage: (25/149) Instrumental delivery: (11/149) Maternal hypertension: (25/149) Preeclampsia: (13/149) Preterm delivery: (17/149) Serious adverse outcome: (3/149) Shoulder dystocia: (0/149) #Perinatal mortality: (2/149) ~LGA: (49/149) SGA: (5/149) Excessive GWG: (61/149) Neonatal hypoglycemia: (15/149) NICU admission: (54/149) NO-PCC: First trimester HbA1c: 7.7 ± SD 1.8 (N = 265) CS delivery: (142/265) Congenital malformations: (12/265) Miscarriage: (36/265) Instrumental delivery: (26/265) Maternal hypertension: (54/265) Preeclampsia: (28/265) Preterm delivery: (47/265) Serious adverse outcome: (24/265) Shoulder dystocia: (6/265) #Perinatal mortality: (8/265) ~LGA: (75/265) SGA: (20/265) Excessive GWG: (80/265) Neonatal hypoglycemia: (22/265) NICU admission: (137/265) |
| 6 | Cyganek (2010) Poland [58] |
PCC: 116 women with (DM-I) NO-PCC: 153 women with (DM-I) |
PCC included: • Intensive diabetes management. |
PCC: Preterm delivery: (22/116) CS delivery: (73/116) NO-PCC: Preterm delivery: (41/153) CS delivery: (116/153) |
| 7 | Cyganek (2016) Poland [64] |
PCC: 210 women with (DM-I) NO-PCC: 313 women with (DM-I) |
PCC included: • Glycemic control, • Assessment of diabetes complications. |
PCC: First trimester HbA1c: 6.4 ± SD 1.1 (N = 210) NO-PCC: First trimester HbA1c: 7.5 ± SD 1.5 (N = 313) |
| 8 |
Dunne (1999) United Kingdom[56] |
PCC: 12 women with (DM-I) NO-PCC: 35 women with (DM-I) |
PCC included: • Glycemic control, • Assessment of diabetes complications. |
PCC: First trimester HbA1c: 7.9 ± SD 1.4 (N = 12) Preterm delivery: (5/12) CS delivery: (9/12) NICU admission: (2/12) LGA: (4/12) SGA: (0/12) Perinatal mortality: (0/12) Congenital malformations: (0/12) NO-PCC: First trimester HbA1c: 9.6 ± SD 2.4 (N = 35) Preterm delivery: (15/35) CS delivery: (26/35) NICU admission: (12/35) LGA: (14/35) SGA: (3/35) Perinatal mortality: (2/35) Congenital malformations: (0/35) |
| 9 | Evers (2004) Netherland [47] |
PCC: 271 women with (DM-I) NO-PCC: 52 women with (DM-I) |
PCC included: • Planned pregnancy, • Folic acid supplementation, • Glycemic control. |
PCC: First trimester HbA1c: 6.4 ± SD 0.9 (N = 271) Congenital malformations: (11/271) NO-PCC: First trimester HbA1c: 7.0 ± SD 1.4 (N = 52) Congenital malformations: (6/ 52) |
| 10 |
Fuhrmann (1986, 1983 & 1984) Germany[27–29] |
PCC: 185 women with (DM-I) NO-PCC: 437 women with (DM-I) |
PCC included: • Hospital based glycemic control, • Glucose self-monitoring. |
PCC: Congenital malformations: (2/185) NO-PCC: Congenital malformations: (31/437) |
| 11 | Galindo (2006) Spain[48] |
PCC: 15 women with (DM-I and DM-II) NO-PCC: 111 women with (DM-I and DM-II) |
PCC included: • Education, • Glycemic control, • Self-monitoring of blood glucose. |
PCC: First trimester HbA1c: 5.8 ± SD 0.98 (N = 15) Congenital malformations: (3/15) NO-PCC: First trimester HbA1c: 6.6 ± SD 1.72 (N = 111) Congenital malformations: (14/111) |
| 12 |
García-Patterso (1997) Spain[41] |
PCC: 66 women with (DM-I and DM-II) NO-PCC: 119 women with (DM-I and DM-II) |
PCC included: • Intensive insulin therapy, • Self-monitoring of blood glucose, • Dietary advice. |
PCC: Miscarriage: (13/66) CS delivery: (47/66) Congenital malformations: (2/66) RDS: (6/66) Neonatal Hypoglycemia: (14/66) Preterm delivery: (15/66) Perinatal mortality: (1/66) SGA: (1/54) NO-PCC: Miscarriage: (15/119) CS delivery: (65/119) Congenital malformations: (10/119) RDS: (12/119) Neonatal Hypoglycemia: (30/119) Preterm delivery: (29/119) Perinatal mortality: (2/119) SGA: (9/105) |
| 13 | Goldman (1986) Israel[53] |
PCC: 44 women with (DM-I) NO-PCC: 31 women with (DM-I) |
PCC included: • Assessment of diabetic complications, • Contraception advice, • Glycemic control and dietary advice. |
PCC: First trimester HbA1c: 7.38 ± SD 0.34 (N = 44) CS delivery: (10/44) Congenital malformations: (0/44) Neonatal Hypoglycemia: (5/44) RDS: (1/44) NO-PCC: First trimester HbA1c: 10.42 ± SD 0.47 (N = 31) CS delivery: (13/31) Congenital malformations: (3/31) Neonatal Hypoglycemia: (8/31) RDS: (4/31) |
| 14 | Gunton (2000) Australia [57] |
PCC: 24 pregnancies (some participants had more than one pregnancy) with (DM-I and DM-II) NO-PCC: 69 pregnancies (some participants had more than one pregnancy) with (DM-I and DM-II) Total N = of women: 61 |
PCC included: • Pregnancies planning by optimizing glycemic control before conception (i.e. intensive insulin regimen treatment and tested the blood glucose frequently). |
PCC: First trimester HbA1c: 6.6 ± SD 2.8 (N = 24) CS delivery: (3/24) NO-PCC: First trimester HbA1c: 8.4 ± SD 5.4 (N = 69) CS delivery: (33/69) |
| 15 | Gunton (2002) Australia[44] |
PCC: 19 pregnancies (some participants had more than one pregnancy) with (DM-I and DM-II) NO-PCC: 16 pregnancies (some participants had more than one pregnancy) with (DM-I and DM-II) Total Number of women:31 |
PCC included: • Pregnancies planning by optimizing glycemic control before conception |
PCC: First trimester HbA1c: 5.5 ± SD 1 (N = 19) CS delivery: (6/19) LGA: (5/19) Congenital malformations: (0/19) NO-PCC: First trimester HbA1c: 6.5 ± SD 1.5 (N = 16) CS delivery: (8/11) Congenital malformations: (1/16) LGA: (4/11) |
| 16 |
Heller (2010) United Kingdom[49] |
PCC: 99 women with (DM-I) [44 treated with Aspart Insulin 55 women treated with Human Insulin] NO-PCC: 223 women with (DM-I) [113 treated with Aspart Insulin 110 women treated with Human Insulin] |
PCC included: • Insulin treatment with either Aspart or human insulin. |
PCC: xFirst trimester HbA1c: 6.24 ± SD 0.69 (N = 99) NO-PCC: xFirst trimester HbA1c: 6.24 ± SD 0.7 (N = 223) |
| 17 |
Hiéronimus (2004) France [46] |
PCC: 24 women with (DM-I and DM-II) NO-PCC: 36 women with (DM-I and DM-II) |
PCC included: Pregnancy programming: - • Pre-conceptional specialized consultation, • Intensification of glycemic self-monitoring, • Optimization of insulin therapy of a preconception HbA1c close to 6%. |
PCC: First trimester HbA1c: 6.79 ± SD 0.72 (N = 24) Congenital malformations: (1/24) NO-PCC: First trimester HbA1c: 8.33 ± SD 1.67 (N = 36) Congenital malformations: (8/36) |
| 18 |
Herman (1999) USA [42] |
PCC: 24 women with (DM-I) NO-PCC: 74 women with (DM-I) |
PCC included: • Education and counselling, • Glycemic control, • Assessment of complications of diabetes such as nephropathy and retinopathy. |
PCC: Miscarriage: (4/24) Congenital malformations: (1/24) NO-PCC: Miscarriage: (3/74) Congenital malformations: (10/74) |
| 19 | Holmes (2017) United Kingdom [51] |
PCC: 58 women with (DM-I and DM-II) NO-PCC: 114 women with (DM-I and DM-II) |
PCC included: • Viewing DVD about preconception counselling. |
PCC: First trimester HbA1c: 6.7 ± SD 0.9 (N = 58) Miscarriage: (1/58) CS delivery: (37/56) Congenital malformations: (2/57) GA at booking(week): 8.3 ± SD 2.3 (N = 58) LGA: (11/57) Maternal hypoglycemia: (8/56) NICU admission: (15/56) NO-PCC: First trimester HbA1c: 7.4 ± SD 1.4 (N = 114) Miscarriage: (16/114) CS delivery: (69/96) Congenital malformations: (2/94) GA at booking(week): 8.3 ± SD 3.2 (N = 109) LGA: (13/93) Maternal hypoglycemia: (18/101) NICU admission: (30/92) |
| 20 |
Jaffiol (2000) France [43] |
PCC: 21 women with (DM-I) NO-PCC: 40 women with (DM-I) |
PCC included: • Education, • Glycemic control, • Self-monitoring of blood glucose, • Contraception. |
PCC: Miscarriage: (2/21) CS delivery: (15/21) GA at booking(week): 6.7 ± SD 1.8 (N = 21) Congenital malformations: (0/21) #Perinatal mortality: (0/21) RDS: (2/21) Neonatal Hypoglycemia: (1/21) Preterm delivery: (7/19) NO-PCC: Miscarriage: (4/40) CS delivery: (21/40) GA at booking(week): 11.1 ± SD 5.3 (N = 40) Congenital malformations: (3/40) #Perinatal mortality: (2/40) RDS: (8/40) Neonatal Hypoglycemia: (7/40) Preterm delivery: (24/34) |
| 21 | Jensen (1986) Denmark[68] |
PCC: 9 women with (DM-I) NO-PCC: 11 women with (DM-I) |
PCC included: • Glycemic control through continuous subcutaneous insulin infusion and conventional treatment. Initiated two months prior to conception. |
PCC: First trimester HbA1c: 6.9 ± SD 0.2 (N = 9) NO-PCC: First trimester HbA1c: 7.2 ± SD 0.5 (N = 11) |
| 22 |
Kallas-Koeman (2012) Canada[60] |
PCC: 71 women with (DM-I and DM-II) NO-PCC: 150 women with (DM-I and DM-II) |
PCC included: • Formal PCC at diabetes pregnancy clinics. |
PCC: xFirst trimester HbA1c: 6.77 ± SD 0.97 (71) NO-PCC: xFirst trimester HbA1c: 7.63 ± SD 1.69 (N = 150) |
| 23 |
Kekäläinen (2016) Finland[65] |
PCC: 96 women with (DM-I) NO-PCC: 49 of women with (DM-I) |
PCC included: • Pregnancy Planning • Optimizing glycemic control • Medications and screening of other health problems. |
PCC: First trimester HbA1c: 6.76 ± SD 0.82 (N = 96) Miscarriage: (15/96) Preeclampsia: (18/96) CS delivery: (47/96) Preterm delivery: (20/96) Congenital malformations: (2/96) LGA: (35/96) Shoulder dystocia: (3/81) Neonatal hypoglycemia: (63/96) Asphyxia: (4/96) RDS: (19/96) NO-PCC: First trimester HbA1c: 8.30 ± SD 1.14 (N = 49) Miscarriage: (14/49) Preeclampsia: (10/49) CS delivery: (24/49) Preterm delivery: (15/49) Congenital malformations: (4/49) LGA: (14 /49) Shoulder dystocia: (3/35) Neonatal hypoglycemia: (30/49) Asphyxia: (4/49) RDS: (9/49) |
| 24 |
Kitzmiller (1991) USA[38] |
PCC: 84 women with (DM-I and DM-II) NO-PCC: 110 women with (DM-I and DM-II) |
PCC included: • Glycemic and dietary control, • Education, • Self-monitoring, • Exercise and contraception. |
PCC: Congenital malformations: (1/84) NO-PCC: Congenital malformations: (12/110) |
| 25 |
Murphy (2010) United Kingdom[59] |
PCC: 181 women with (DM-I and DM-II) NO-PCC: 495 women with (DM-I and DM-II) |
PCC included: • Glycemic control, • Folic acid supplementation, • Smoking cessation, • Education and preconception counselling. |
PCC: Miscarriage: (28/181) LGA: (120/145) Congenital malformations: (1/152) Perinatal mortality: (1/152) CS delivery: (99/181) Preterm delivery: (50/150) SGA: (7/145) NO-PCC: Miscarriage: (71/495) LGA: (284/372) Congenital malformations: (23/408) Perinatal mortality: (9/408) CS delivery: (222/495) Preterm delivery: (116/397) SGA: (32/372) |
| 26 |
Neff (2014) Ireland[63] |
PCC: 70 women with (DM-I) NO-PCC: 394 women with (DM-I) |
PCC included: • Insulin treatment which was continuous subcutaneous infusion and multiple daily injection. |
PCC: First trimester HbA1c: 6.9 ± SD 0.9 (N = 70) LGA: (17/70) SGA: (4/63) CS delivery: (47/70) Miscarriage: (7/70) Preterm delivery: (11/70) GA at booking(week): 6 ± SD 2 (N = 70) NO-PCC: First trimester HbA1c: 7.8 ± SD 1.5 (N = 394) LGA: (83/394) SGA: (27/331) CS delivery: (213/394) Miscarriage: (63/394) Preterm delivery: (59/394) GA at booking(week): 8 ± SD 6 (N = 394) |
| 27 |
Gutaj (2013) Poland[61] |
PCC: 43 women with (DM-I and DM-II) NO-PCC: 108 women with (DM-I and DM-II) |
PCC included: • Pregnancy planning, • Counseling delivered by a diabetes specialist, • Glycemic control by making necessary changes in pharmacotherapy, • Controlling chronic diabetic complications. |
PCC: xFirst trimester HbA1c: 6.15 ± SD 0.82 (N = 43) NO-PCC: xFirst trimester HbA1c: 8.13 ± SD 01.85 (N = 108) |
| 28 |
Rosenn (1991) USA[39] |
PCC: 28 women with (DM-I) NO-PCC: 71 women with (DM-I) |
PCC included: • Dietary advice • Glycemic control |
PCC: First trimester HbA1c:8.5 ± SD 0.22 (N = 28) Congenital malformations: (0/28) Miscarriage: (7/28) GA at booking(week): 5.5 ± SD 0.2 (N = 28) NO-PCC: First trimester HbA1c: 10 ± SD 0.32 (N = 71) Congenital malformations: (1/71) GA at booking(week): 6.8 ± SD 0.18 (N = 71) Miscarriage: (17/71) |
| 29 |
Rowe (1987) United Kingdom[54] |
PCC: 14 women with (DM-I) NO-PCC: 7 women with (DM-I) |
PCC included: • Glycemic control, • Counseling, • Blood glucose self-monitoring. |
PCC: First trimester HbA1c: 9.8 ± SD 2.0 (N = 14) Congenital malformations: (0/14) NO-PCC: First trimester HbA1c: 13.7 ± SD 3.3 (N = 7) Congenital malformations: (2/7) |
| 30 |
Steel (1982 & 1990) United Kingdom[32, 33] |
PCC: 143 women with (DM-I) NO-PCC: 96 women with (DM-I) |
PCC included: • Education, • Glycemic control, • Contraception. |
PCC: First trimester HbA1c: 8.4 ± SD 1.3 (N = 143) Congenital malformations: (2/143) Maternal hypoglycemia: (38/143) NO-PCC: First trimester HbA1c: 10.5 ± SD 2 (N = 96) Congenital malformations: (10/96) Maternal hypoglycemia: (8/96) |
| 31 |
Temple (2006a & & 2006b) United Kingdom[30, 31] |
PCC: 110 women with (DM-I) NO-PCC: 180 women with (DM-I) |
PCC included: • Glycemic control, • Folic acid supplementation, • Smoking cessation, • Education. |
PCC: First trimester HbA1c: 5.9 ± SD 0.9 (N = 110) GA at booking(week): 6.6 ± SD 1.8 (N = 110) Maternal hypoglycemia: (47/110) Miscarriage: (6/110) Preterm delivery: (28/110) Preeclampsia: (14/110) CS delivery: (73/110) LGA: (48/110) Congenital malformations: (2/110) #Perinatal mortality: (1/110) NO-PCC: First trimester HbA1c: 6.6 ± SD 1.2 (N = 180) GA at booking(week): 8.3 ± SD 2.6 (N = 180) Maternal hypoglycemia: (65/180) Preeclampsia: (22/180) CS delivery: (118/180) Preterm delivery: (61/180) Congenital malformations: (11/180) Miscarriage: (22/180) LGA: (78/180) # Perinatal mortality: (6/180) |
| 32 |
Willhoite (1993) USA[40] |
PCC: 62 women with (DM-I and DM-II) NO-PCC: 123 women with (DM-I and DM-II) |
PCC included: • Counseling by health professional. |
PCC: Perinatal mortality: (4/62) Congenital malformations: (1/62) NO-PCC: Perinatal mortality: (26/123) Congenital malformations: (8/123) |
| 33 |
Wong (2013) United Kingdom[62] |
PCC: 52 women with (DM-I and DM-II) NO-PCC: 109 women with (DM-I and DM-II) |
PCC included: • HbA1c monitoring in each trimester, • Insulin treatment, • Pregnancies planning, • Diabetes management by a diabetes (i.e. endocrinologists or general physicians with a special interest in diabetes), • Following up throughout pregnancy with the involvement of dietitians and diabetes educators. |
PCC: xFirst trimester HbA1c: 7.37 ± SD 1.95 (N = 52) Congenital malformations: (1/52) Perinatal mortality: (3/52) NO-PCC: xFirst trimester HbA1c: 8.33 ± SD 2.33 (N = 109) Congenital malformations: (10/109) Perinatal mortality: (12/109) |
| 34 |
Wotherspoon (2017) United Kingdom [52] |
PCC: 455 women with (DM-I) NO-PCC: 292 women with (DM-I) |
PCC included: • Pregnancy planning, • Pre-pregnancy counselling (as structured advice about maintaining good blood glucose control and healthy lifestyle (with respect to diet, exercise, BMI, smoking status and alcohol consumption) before trying to become pregnant, including the need to take folate supplements. |
PCC: First trimester HbA1c: 7.0 ± SD 0.8 (N = 455) Pre-eclampsia: (74/448) CS delivery: (307/454) Perinatal mortality: (12/449) SGA: (26/446) LGA: (230/446) Congenital malformations: (15/454) NICU admission: (218/436) NO-PCC: First trimester HbA1c: 7.5 ± SD 1.1 (N = 292) Pre-eclampsia: (49/286) CS delivery: (200/286) Perinatal mortality: (6/284) SGA: (31/284) LGA: (149/284) Congenital malformations: (13/291) NICU admission: (178/277) |
DM-I: Diabetes Mellitus type I, DM-II: Diabetes Mellitus type II, GA: Gestational Age, GWG: Gestational Weight Gain, HbA1c: Glycated Haemoglobin, LGA: Large for Gestational Age, NICU: Neonatal Intensive Care Unit, NO-PCC: No Preconception Care, PCC: Preconception Care, RDS: Respiratory Distress Syndrome, SGA: Small for Gestational Age
x Calculated mean
~ LGA and macrosomia
# sum of stillbirth and neonatal death