Effect of Lockdown Period of COVID-19 Pandemic on Maternal Weight Gain, Gestational Diabetes, and Newborn Birth Weight

Abstract

Objective

This study aimed to determine whether the lockdown period of the initial novel coronavirus disease 2019 (COVID-19) surge in New York affected gestational weight gain (GWG), newborn birth weight (BW), and the frequency of gestational diabetes mellitus (GDM). Maternal and newborn outcomes during the first wave of the pandemic were compared with those during the same timeframe in the previous 2 years.

Study Design

Retrospective cross-sectional study of all live singleton term deliveries from April 1 to July 31 between 2018 and 2020 at seven hospitals within a large academic health system in New York. Patients were excluded for missing data on: BW, GWG, prepregnancy body mass index, and gestational age at delivery. We compared GWG, GDM, and BW during the pandemic period (April–July 2020) with the same months in 2018 and 2019 (prepandemic) to account for seasonality. Linear regression was used to model the continuous outcomes of GWG and BW. Logistic regression was used to model the binary outcome of GDM.

Results

A total of 20,548 patients were included in the study: 6,672 delivered during the pandemic period and 13,876 delivered during the prepandemic period. On regression analysis, after adjustment for study epoch and patient characteristics, the pandemic period was associated with lower GWG (β = −0.46, 95% confidence interval [CI]: −0.87 to −0.05), more GDM (adjusted odds ratio [aOR] = 1.24, 95% CI: 1.10–1.39), and no change in newborn BW (β = 0.03, 95% CI: −11.7 to 11.8) compared with the referent period. The largest increases in GDM between the two study epochs were noted in patients who identified as Hispanic (8.6 vs. 6.0%; p < 0.005) and multiracial/other (11.8 vs. 7.0%; p < 0.001).

Conclusion

The lockdown period of the pandemic was associated with a decrease in GWG and increase in GDM. Not all groups were affected equally. Hispanic and multiracial patients experienced a larger percentage change in GDM compared with non-Hispanic white patients.

In March 2020, during the first wave of the novel coronavirus disease 2019 (COVID-19) outbreak in New York, the state’s governor ordered all nonessential workers to stay at home and for all nonessenties to close.¹ This policy, sometimes referred to as shelter-in-place or lockdown, aimed to reduce the spread of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). In June 2020, a multiphase reopening plan was implemented. Studies have demonstrated a reduction in physical activity and an increase in negative dietary habits during pandemic-related lockdowns²; similar to behaviors that have been observed in pregnant patients.^3-5 However, few large studies have evaluated the impact of the lockdown measures on pregnancy outcomes associated with diet and exercise behaviors, such as gestational diabetes mellitus (GDM), gestational weight gain (GWG), and newborn birth weight (BW).^6,7 Overall, studies on perinatal outcomes during this period have yielded conflicting results^8,9 which may be related to population-specific factors.

Women who experience excessive GWG and GDM are at increased risk for preeclampsia, cesarean section, and subsequent diagnosis of type-2 diabetes; their offspring are at increased risk for macrosomia, neonatal hypoglycemia, hyperbilirubinemia, shoulder dystocia, birth trauma, and stillbirth.¹⁰ Risk factors for GDM include genetic predisposition (first-degree relative with diabetes), obesity, history of GDM, previous delivery of a newborn weighing ≥4,000 g, high-risk racial or ethnic group (Black, Hispanic, Native American, American Indian, Asian American, and Pacific Islander), hypertension, polycystic ovarian syndrome, and others. Risk factors for excessive GWG include maternal age, obesity, food insecurity, chronic stress, and mood disorders.¹¹

The prevalence of obesity and diabetes in each population is strongly affected by nonmedical factors in the social and physical environment.^12-14 These factors, known as social determinants of health (SDH), include income, education, employment, minority status, language, housing, access to transportation, and many others. The pandemic produced significant disruptions in the provision of health care services such as closure of outpatient medical offices, urgent care facilities being converted to COVID-19 testing centers, and hospitals significantly restricting visitation. During the lockdown, access to telehealth appointments was not equally distributed.^15-18 Patients of lower socioeconomic status, non-English speakers, those with public health insurance, and those who belong to minority racial and ethnic groups had reduced access to obstetrical care and nutrition counseling, and this may have negatively impacted pregnancy outcomes.^15-18

The objective of this study was to determine whether the lockdown period of the pandemic, during the initial COVID-19 surge in New York, was associated with a change in GWG, newborn BW, and the frequency of GDM. Maternal and newborn outcomes during the first wave of the pandemic were compared with those during the same time frame in the previous 2 years. Clinical and sociodemographic factors associated with these outcomes were also evaluated to control for potential confounders. We hypothesized that decreased physical activity, poor dietary habits, and interruption of routine prenatal services, particularly in high-risk groups, would result in excessive GWG and an increase in diabetes and macrosomia.

Materials and Methods

This retrospective cross-sectional study evaluated all live singleton term deliveries that occurred from April 1 to July 31 each year between 2018 and 2020 at seven hospitals within a large academic health system in New York. Patients were excluded for missing data on BW, GWG, prepregnancy body mass index (BMI), and gestational age at delivery. Pregnancies complicated by fetal anomalies or abnormal genetic testing were not excluded. Medical comorbidities that could affect maternal weight such as chronic steroid therapy or uncontrolled thyroid disease were not evaluated. For patients with more than one delivery during the study period, only the first delivery was included for analysis. We compared GWG, prevalence of GDM, and BW during the pandemic period (April–July 2020) with the same months in 2018 and 2019 (prepandemic) to account for seasonality. The pandemic era patients were further classified based on SARS-CoV-2 polymerase chain reaction (PCR) testing at delivery, if performed. Universal PCR testing was implemented in April 2020. Due to limited testing capabilities in early April, some hospitals were only testing symptomatic patients and those with known or suspected exposure to the virus. However, by May 2020, all seven hospitals had fully implemented universal PCR testing for SARs-CoV-2 on admission to labor and delivery.

Data were obtained from the enterprise electronic health record system (Sunrise Clinical Manager, Allscripts Corp., Chicago, IL), including patient demographic information, clinical characteristics, and pregnancy outcomes. Self-reported race and ethnicity data were collected from pre-specified categories. Self-reported height, weight, and GWG, which are routinely documented on admission to the hospital for delivery, were collected. Patient ZIP codes were linked to neighborhood socioeconomic data from the U.S. Census Bureau’s American Community Survey.¹⁹

The primary outcomes were GWG in pounds (lbs; continuous variable), newborn BW in grams (continuous variable), and GDM (binary variable). A secondary outcome was exceeding the Institute of Medicine (IOM) guidelines for GWG based on prepregnancy BMI.²⁰ The diagnosis of GDM was based on two elevated glucose values on a 3-hour 100-g oral glucose tolerance test using the thresholds established by Carpenter and Coustan.²¹ Alternatively, a presumptive diagnosis of GDM was made for cases in which a 1-hour 50-g glucose challenge test yielded a glucose concentration of ≥200 mg/dL.^22,23 Standard BW-related outcomes were evaluated, including macrosomia, low BW (LBW), large for gestational age (LGA), and small for gestational age (SGA). The diagnosis of macrosomia was BW greater than 4,500 g,²⁴ and the diagnosis of LBW was less than 2,500 g.²⁵ SGA and LGA were defined as less than the 10th percentile and greater than the 90th percentile for gestational age, respectively.

Descriptive statistics were used to characterize the data. Results are presented as mean and standard deviation or median and interquartile range, as appropriate. Comparisons for continuous variables were performed with the Mann–Whitney test/t-test, or one-way analysis of variance (ANOVA)/Kruskal–Wallis test, as appropriate. Categorical variables were expressed as frequency and percentage. Each categorical outcome was examined using the Chi-square test or Fisher’s exact test, as appropriate.

Linear regression was used to model the continuous outcomes of GWG and BW. Logistic regression was used to model the binary outcome of GDM. In each case, the basic model included the main exposure (study epoch) and potential confounders which included: month of delivery (if during pandemic, nominal), GDM (removed from GDM model), pregestational diabetes (removed from GDM model), GWG (removed from GWG model), maternal age, gestational age at delivery, parity, race and ethnicity, marital status, preferred language, insurance type, prepregnancy BMI, and neighborhood socioeconomic conditions. Potential interactions between variables were also added to the basic model. All first-degree predictors remained in the model regardless of the p-value of their coefficients but only interacting terms with p < 0.05 were retained in the model. Odds ratios (ORs) and coefficients (β) are presented, as appropriate, with 95% confidence intervals (CIs) for all predictor variables. Effect sizes for ORs were characterized as very small, small, medium, and large, and defined as <1.55, 1.55 to 2.79, 2.80 to 4.99, and >5.00, respectively.²⁶ Statistical significance was defined as two-sided p < 0.05. Statistical analyses were performed with RStudio 1.1.463 built on R 3.5.1 and/or SAS Studio 3.8 Enterprise Edition build on SAS 9.04 (SAS Inc, Cary, NC.).

The Northwell Health Institutional Review Board approved this study as minimal-risk research using data collected for routine clinical practice and waived the requirement for informed consent (IRB no.: 20–0937; initial approval dated: October 14, 2020).

Results

A total of 20,548 patients were included in the study: 6,672 delivered during the pandemic period and 13,876 delivered during the prepandemic period (►Fig. 1). Baseline patient characteristics for each epoch are presented in ►Table 1. The study population had a mean maternal age of 31 years, 57% were multiparous, 18% had obesity prior to pregnancy, 37% had public health insurance, and 46% were non-Hispanic White (the largest racial and ethnic group within our study). There was a 5% decrease in non-Hispanic White patients during the pandemic compared with the prepandemic period.

Fig. 1.

Study participants. BMI, body mass index; BW, birth weight; GWG, gestational weight gain.

Table 1.

Comparison of maternal characteristics for term singleton deliveries between the prepandemic period (April–July 2018 and 2019) and the pandemic period (April–July 2020)

Characteristic	Prepandemic period (n = 13,876)	Pandemic period (n = 6,672)	p-Value
Maternal age (y)	31.3 ± 5.4	31.4 ± 5.4	0.22
≥35 weeks	3,889 (28.0)	1,899 (28.5)	0.53
Race and ethnicity
Non-Hispanic White	6,513 (46.9)	2,972 (44.5)	<0.001
Non-Hispanic Black	1,626 (11.7)	785 (1 1.8)
Hispanic/Latino	2,286 (16.5)	1,244 (18.6)
Asian	1,630 (1 1.7)	822 (12.3)
Other/multiracial	1,265 (9.1)	608 (9.1)
Unknown/declined	556 (4.0)	241 (3.6)
Parity
0	6,093 (43.9)	2,793 (41.9)	0.003
1	4,733 (34.1)	2,286 (34.3)
≥2	3,050 (22.0)	1,593 (23.9)
Prepregnancy BMI (kg/m2)	23.9 [21.2, 28.0]	24.6 [21.5, 28.5]	<0.001
< 18.5 (underweight)	659 (4.7)	232 (3.5)	<0.001
18.5–24.9 (normal)	7,513 (54.1)	3,465 (51.9)
25–29.9 (overweight)	3,325 (24.0)	1,710 (25.6)
30–34.9 (class I obesity)	1,461 (10.5)	807 (12.1)
35–39.9 (class II obesity)	585 (4.2)	310 (4.6)
≥40 (class III obesity)	333 (2.4)	148 (2.2)
Married	9,708 (70.0)	4,575 (68.6)	0.04
Public health insurance	5,034 (36.3)	2,526 (37.9)	<0.001
Preferred language English	11,677 (84.2)	5,701 (85.4)	0.02
Neighborhood characteristics
Median household income ($)	45,749 [34,336, 64,885]	44,669 [33,936, 64,360]	0.004
Less than high school education (%)	9.0 [4.3, 16.6]	9.3 [4.4, 16.8]	0.005
Unemployment rate (%)	4.8 [3.9, 6.3]	4.8 [4.0, 6.3]	0.07
Receiving SSI/SNAP (%)	9.3 [4.4, 16.8]	17.4 [8.0, 27.8]	<0.001
Medical comorbidities
Chronic hypertension	282 (2.0)	181 (2.7)	0.002
Pregestational diabetes	122 (0.9)	75 (1.1)	0.11
Hypertensive disorder of pregnancy	493 (3.6)	327 (4.9)	<0.001

BMI, body mass index; SSI, supplemental security income; SNAP, supplemental nutrition assistance program

Note: Data presented as mean ± standard deviation, number (%), or median [interquartile range].

On Chi-square analysis, there was a statistically significant decrease in GWG (28.7 vs. 30.9 lbs; p < 0.001) and increase in GDM (8.4 vs. 6.5%; p < 0.001) during the pandemic compared with the prepandemic period (►Table 2). The percentage of patients with inadequate GWG (i.e., failed to meet IOM guidelines) increased slightly during the pandemic (23.0 vs. 21.2%). When comparing the two epochs, there was no significant difference in newborn BW (p = 0.39). Furthermore, there were no changes in the rate of macrosomia, LBW, LGA, or SGA at term. However, there was an increase in shoulder dystocia (1.4 vs. 1.0%; p = 0.006) and a decrease in phototherapy (4.5 vs. 5.5%; p = 0.002) during the pandemic period compared with the prepandemic period. The largest increases in GDM between the two study epochs were noted in patients who identified as Hispanic (8.6 vs. 6.0%; p < 0.005 on Chi-square analysis) and multiracial/other (11.8 vs. 7.0%; p < 0.001 on Chi-square analysis) with a percentage change of 43 and 69%, respectively (►Table 2). Primary study outcomes are compared separately for each BMI classification in ►Table 3. GDM was increased within all individual BMI groups during the pandemic except for those who were underweight prior to pregnancy. However, the results were only statistically significant (on Chi-square analysis) in the normal, overweight, and class-1 obesity groups which may be attributable to the smaller sample size in the remaining BMI groups. No differences were seen in newborn BW and most individual BMI groups did not have significant changes in GWG when comparing the two study epochs.

Table 2.

Comparison of pregnancy outcomes for term singleton deliveries between the prepandemic period (April–July 2018 and 2019) and the pandemic period (April–July 2020)

Outcome	Prepandemic period (n = 13,876)	Pandemic period (n = 6,672)	p-Value
Maternal
Gestational weight gain (lb)	30.9 [22.1, 39.7]	28.7 [22.1, 37.5]	<0.001
Excessivea	6,724 (48.5)	3,158 (47.3)	0.009
Adequatea	4,216 (30.4)	1,977 (29.6)
Inadequatea	2,936 (21.2)	1,537 (23.0)
Gestational diabetes	907 (6.5)	559 (8.4)	<0.001
Non-Hispanic White	341/6,513 (5.2)	191/2,972 (6.4)	0.02
Non-Hispanic Black	99/1,626 (6.1)	57/785 (7.3)	0.28
Hispanic/Latino	138/2,286 (6.0)	107/1,244 (8.6)	0.005
Asian	178/1,630 (10.9)	118/822 (14.4)	0.01
Other/multiracial	89/1,265 (7.0)	72/608 (11.8)	<0.001
Unknown/declined	62/556 (11.2)	14/241 (5.8)	0.02
Newborn
Gestational age at delivery (wk)	39.3 ± 1.0	39.3 ± 1.0	0.008
Birth weight (g)	3,357 ± 445	3,352 ± 444	0.39
Macrosomia	143 (1.0)	52 (0.8)	0.10
Low birth weight	322 (2.3)	153 (2.3)	0.94
Small for gestational age	1,317 (9.5)	597 (8.9)	0.22
Large for gestational age	1,433 (10.3)	678 (10.2)	0.73
Phototherapy	766 (5.5)	300 (4.5)	0.002
Shoulder dystocia	133 (1.0)	93 (1.4)	0.006

Data presented as mean ± standard deviation, number (%), or median [interquartile range].

^aBased on Institute of Medicine (IOM) guidelines for gestational weight gain based on prepregnancy body mass index.

Table 3.

Primary study outcomes by body mass index (BMI) classification between the prepandemic period (April–July 2018 and 2019) and the pandemic period (April–July 2020)

Outcome	Prepandemic period (n = 13,876)	Pandemic period (n = 6,672)	p-Value
Prepregnancy BMI (kg/m2)
< 18.5 (underweight)	n = 659	n = 232
Gestational weight gain (lb)	30.9 [24.3, 37.5]	30.9 [24.3, 39.7]	0.87
Gestational diabetes	26 (3.9)	5 (2.2)	0.20
Newborn birth weight (g)	3,210 ± 407	3,201 ± 430	0.78
18.5–24.9 (normal)	n = 7,513	n = 3,465
Gestational weight gain (lb)	30.9 [24.3, 39.7]	30.9 [24.3, 39.7]	0.03
Gestational diabetes	336 (4.5)	190 (5.5)	0.02
Newborn birth weight (g)	3,333 ± 427	3,325 ± 429	0.38
25–29.9 (overweight)	n = 3,325	n = 1,710
Gestational weight gain (lb)	28.7 [19.8, 39.7]	28.7 [19.8, 37.5]	0.14
Gestational diabetes	268 (8.1)	182 (10.6)	0.003
Newborn birth weight (g)	3,400 ± 448	3,381 ± 454	0.15
30–34.9 (class I obesity)	n = 1,461	n = 807
Gestational weight gain (lb)	26.5 [17.6, 35.3]	24.3 [15.4, 35.3]	0.03
Gestational diabetes	141 (9.7)	123 (15.2)	<0.001
Newborn birth weight (g)	3,402 ± 491	3,413 ± 455	0.61
35–39.9 (class II obesity)	n = 585	n = 310
Gestational weight gain (lb)	22.1 [13.2, 30.9]	19.8 [11.0, 30.9]	0.61
Gestational diabetes	78 (13.3)	51 (16.5)	0.21
Newborn birth weight (g)	3,430 ± 484	3,437 ± 471	0.85
≥40 (class III obesity)	n = 333	n = 148
Gestational weight gain (lb)	19.8 [6.6, 30.9]	17.6 [4.4, 30.9]	0.56
Gestational diabetes	58 (17.4)	31 (20.9)	0.36
Newborn birth weight (g)	3,457 ± 496	3,374 ± 498	0.09

Data presented as mean ± standard deviation, number (%), or median [interquartile range]

During the pandemic period, 6.8% (n = 451) of the patients were SARS-CoV-2 PCR positive at delivery, 89.0% (n = 5,938) were PCR negative, and 4.2% (n = 283) did not have PCR test results available for review. Patients with negative PCR testing were more than twice as likely to have GDM than those with positive PCR testing (8.7 vs. 4.2%, respectively; OR = 2.17, 95% CI: 1.39–3.56 on Chi-square analysis). In addition, those with negative PCR testing had greater GWG (30.3 vs. 27.3 lbs; p < 0.001) and greater newborn BW (3,356 vs. 3,311 g; p = 0.04) compared with those with positive PCR testing.

►Table 4 shows regression models that evaluate the effect of study epoch (prepandemic versus pandemic) on GWG, GDM, and BW, after adjustment for patient characteristics. Compared with the referent period, the pandemic period was associated with less GWG (β = −0.46, 95% CI: −0.87 to −0.05), more GDM (aOR = 1.24, 95% CI: 1.10–1.39), and no change in newborn BW (β = 0.03, 95% CI: −11.7–11.8). Across all study years, factors associated with increased GWG included non-Hispanic black race and ethnicity, preferred language as English, negative prenatal testing for GDM, and public health insurance. Factors associated with increased newborn BW included diabetes (pregestational or gestational), GWG, maternal age, parity, gestational age at delivery. Factors associated with GDM included Hispanic ethnicity, maternal age, and increased prepregnancy BMI. Several statistically significant two-way interactions are shown in ►Table 4.

Table 4.

Regression models to evaluate the outcomes of gestational weight gain (GWG), newborn birth weight (BW), and gestational diabetes (GDM) adjusting for study epoch (prepandemic vs. pandemic) and patient characteristics

	Gestational weight gaina		Newborn birth weighta		Gestational diabetesb
Characteristic	β (95% CI)	p-Value	β (95% CI)	p-Value	OR (95% CI)	p-Value	Effect size
Study epoch
Prepandemic	Reference		Reference		Reference
Pandemic	−0.46 (−0.87, −0.05)	0.03	0.03 (−11.7, 11.8)	1.00	1.24 (1.10, 1.39)	<0.001	Very small
Delivery month
April	Reference		Reference		Reference
May	0.37 (−0.19, 0.93)	0.19	−1.53 (−17.5, 14.4)	0.85	1.15 (0.97, 1.35)	0.10	Very small
June	0.48 (−0.07, 1.04)	0.09	9.30 (−6.5, 25.0)	0.25	1.11 (0.95, 1.31)	0.20	Very small
July	0.26 (−0.29, 0.81)	0.35	1.52 (−14.1, 17.1)	0.85	1.07 (0.91, 1.26)	0.42	Very small
Gestational diabetes	−3.91 (−5.73, −2.09)	<0.001	75.5 (53.7, 97.3)	<0.001	–	–	–
Pregestational diabetes	−2.29 (−6.27, 1.70)	0.26	201 (145, 257)	<0.001	–	–	–
Gestation weight gain (lb)	–	–	6.47 (6.07, 6.86)	<0.001	0.98 (0.98, 0.99)	<0.001	Very small
Maternal age (y)	−0.04 (−0.08, −0.001)	0.05	3.91 (2.75, 5.08)	<0.001	1.08 (1.07, 1.09)	<0.001	Very small
Gestational age at delivery (wk)	0.85 (0.66, 1.04)	<0.001	162 (157, 168)	<0.001	0.69 (0.66, 0.73)	<0.001	Very small
Parity	−0.65 (−0.82, −0.48)	<0.001	32.9 (28.0, 37.8)	<0.001	0.93 (0.88, 0.97)	0.004	Very small
Race and ethnicity
Hispanic/Latino	Reference		Reference		Reference
Asian	−5.28 (−10.4, −0.11)	0.05	−54.8 (−190, 80.9)	0.43	1.25 (0.62, 2.55)	0.53	Very small
Multiracial/other	−1.55 (−6.30, 3.21)	0.52	−96.4 (−225, 32.4)	0.14	0.41 (0.20, 0.84)	0.02	Small
Non-Hispanic Black	6.74 (1.56, 11.9)	0.01	−120 (−257, 15.9)	0.08	0.25 (0.09, 0.66)	0.006	Medium
Non-Hispanic White	−1.44 (−5.35, 2.48)	0.47	−122 (−227, −16.1)	0.02	0.60 (0.33, 1.10)	0.10	Very small
Marital status: married	−0.80 (−1.75, 0.14)	0.10	12.3 (−1.12, 25.6)	0.07	0.85 (0.64, 1.12)	0.23	Very small
Language: non-English	−1.62 (−2.21, −1.03)	<0.001	13.4 (−3.29, 30.16)	0.12	1.09 (0.91, 1.29)	0.35	Very small
Health insurance
Public	Reference		Reference		Reference
Private	0.60 (0.13, 1.08)	0.01	7.63 (−5.83, 21.10)	0.27	0.97 (0.85, 1.11)	0.67	Very small
Self-pay	2.29 (−0.53, 5.11)	0.11	−15.0 (−95.3, 65.4)	0.72	0.86 (0.30, 1.98)	0.76	Very small
Prepregnancy BMI	−0.67 (−0.75, −0.59)	<0.001	8.75 (6.41, 11.1)	<0.001	1.06 (1.05, 1.07)	<0.001	Very small
Neighborhood
Annual household income ($)	−0.48 (−1.84, 0.87)	0.49	14.6 (−23.6, 52.8)	0.46	0.82 (0.55, 1.22)	0.33	Very small
Education: less than high school (%)	−0.55 (−1.16, 0.06)	0.08	−7.98 (−25.4, 9.42)	0.37	0.71 (0.55, 0.90)	0.006	Very small
Unemployment rate (%)	1.05 (−0.58, 2.67)	0.21	20.5 (−21.2, 62.1)	0.34	1.09 (0.89, 1.34)	0.42	Very small
Households receiving SSI/SNAP (%)	0.31 (−0.49, 1.10)	0.46	−5.05 (−15.9, 5.83)	0.36	0.95 (0.85, 1.06)	0.34	Very small
Two-way interactions
GDM: NH Black	3.80 (0.88, 6.73)	0.01	–	–	–	–	–
Married: multiracial/other	−1.85 (−3.28, −0.41)	0.01	–	–	1.72 (1.15, 2.58)	0.009	Small
Married: NH White	−1.59 (−2.82, −0.37)	0.01	–	–	–	–	–
BMI: multiracial/other	0.20 (0.08, 0.32)	0.002	5.11 (1.71, 8.51)	0.004	–	–	–
BMI: NH White	0.34 (0.24, 0.44)	<0.001	5.62 (2.86, 8.39)	<0.001	–	–	–
BMI: Asian	0.22 (0.07, 0.36)	0.003	–	–	–	–	–
SSI/SNAP: NH White	−0.97 (−1.80, −0.15)	0.02	–	–	–	–	–
Unemployment: Asian	–	–	−62.3 (−123, −1.89)	0.04	–	–	–
Unemployment: NH Black	−2.73 (−5.17, −0.29)	0.03	–	–	–	–	–
Education: Asian	–	–	–	–	1.39 (1.08, 1.78)	0.01	Very small
Education: multiracial/other	–	–	–	–	1.43 (1.11, 1.85)	0.006	Very small
Education: NH Black	–	–	–	–	1.55 (1.09, 2.23)	0.02	Small
Observations	19,625		19,625		19,625
Adjusted R2	0.08		0.23		–

Abbreviations: BMI, body mass index; CI, confidence interval; GDM, gestational diabetes; NH, non-Hispanic; OR, odds ratio; SSI, supplemental security income; SNAP, supplemental nutrition assistance program.

^aLinear regression.

^bLogistic regression.

Discussion

The pandemic lockdown period (April–July 2020) was associated with a small decrease in GWG, an increase in the frequency of GDM, and no change in newborn BW compared with the prepandemic period. Overall, the lockdown period of the pandemic appears to be a small contributor to GWG and GDM. These findings are reassuring and indicate that, during a state of emergency, mitigation measures such as lockdowns do not have a large clinical effect on these pregnancy outcomes. Nevertheless, concerns remain that not all groups are affected equally due to racial and ethnic disparities that exist. Notably, we observed that some minoritized groups experienced a larger percentage change in GDM during the pandemic than the most prevalent group (non-Hispanic White). This increase in GDM may reflect an increase in the prevalence of food insecurity primarily affecting lower socioeconomic groups during the lockdown period of the pandemic leading to suboptimal maternal nutrition.²⁷

Some of our findings are contrary to our expectations. In the general population, increases in weight gain^28-32 and impaired glucose regulation³³ have been observed during COVID-19 lockdowns. Some investigators have even noted increased pandemic-related weight gain in women compared with men,³⁰ but others have observed the opposite.³¹ Psychosocial stressors negatively impact physical activity and dietary choices during pregnancy.³⁴ Social isolation and interruption of health care services during the lockdown had harmful effects on mental health^35-37 which may have been even more pronounced in pregnant women.³⁸ During the lockdown, increased GWG has been seen in some populations.³⁹ Based on our review of the literature, there remains limited data on the effect of lockdown measures on GWG, particularly in the United States. Recently, one large U.S. population-based study demonstrated an increase in GDM during the first 10 months of the pandemic compared with the previous year.⁴⁰ The authors of that study used deidentified administrative claims data and were unable to evaluate more granular patient data such as GWG and BW.

Newborn outcomes were also affected by the lockdown period of the pandemic. Our observation that shoulder dystocia increased compared with the prepandemic period is consistent with the concurrent increase in GDM. Prior studies have demonstrated that maternal diabetes is an independent risk factor for shoulder dystocia.⁴¹ Maternal obesity and GWG further increase this risk.⁴² Anthropometric differences in the neonates of diabetic mothers include significantly greater shoulder-to-head and chest-to-head ratios.⁴³ The decrease in phototherapy during the pandemic period is more difficult to interpret. An increase in GDM would be expected to increase the rate of neonatal jaundice and subsequent treatment. Therefore, this apparent contradiction may be related to early discharge protocols⁴⁴ to avoid prolonged neonatal hospitalizations and nosocomial SARS-CoV-2 transmission.

SARS-CoV-2 infection at the time of hospitalization for delivery did not significantly impact GWG, GDM, or BW because these parameters are a function of gestational age and change over a longer period of time. For this reason, PCR status was not included in our regression analyses. Nevertheless, since patients from racial and ethnic minority groups were disproportionately infected with the virus during the first wave of the pandemic,⁴⁵ we did evaluate these outcomes for completeness, but the results should be interpreted cautiously. Our finding that SARS-CoV-2 negative patients had higher rates of GDM is somewhat surprising and may be a function of low numbers or disruptions in prenatal care, including lack of GDM testing.

Strengths and Limitations

Our study has several strengths. The health system serves a diverse population within New York City and Long Island, the epicenter of the initial outbreak in the United States. A single electronic medical record system is used for all seven hospital sites allowing for greater uniformity of data collection. Shared institutional protocols ensure that the same glucose thresholds were used for the diagnosis of GDM, and that during the pandemic, SARS-CoV-2 PCR testing was universally performed upon admission to labor and delivery.

This study has several limitations, including its retrospective nature, data obtained from a single health system, short epochs, narrow gestational age window, uncertain effects from outmigration during the pandemic period,⁴⁶ uncertain timing of GDM diagnosis, and unknown glycemic control. Furthermore, it is possible that patients who were earlier in gestational age at the time of the lockdown, who were omitted from this study because they delivered after July 2020, were more affected. However, we did adjust for month of delivery, and we did not observe any effect. That is, patients who delivered in July, who were exposed to 4 months of lockdown, did not have different results than those who delivered in April, and who were only exposed to 1 month of lockdown. Self-reported GWG at delivery is subjected to recall or reporting bias. Disruptions in routine prenatal care during the pandemic may have resulted in either late GDM testing (>28 weeks of gestational age) which may increase the likelihood of a positive test or lack of testing which would erroneously decrease the overall rate of GDM.^47,48 In this study, GDM cases were identified by clinical documentation and billing codes; laboratory results were not consistently available to confirm GDM diagnosis. Patient-level data on income, occupation, employment status, and educational attainment were not analyzed. Finally, only term deliveries were evaluated, and it is possible that during the pandemic patients with both GDM and other comorbid conditions required preterm delivery secondary to inconsistent care.

Conclusion

In conclusion, the lockdown period of the pandemic had subtle effects on GWG and GDM which were not evenly distributed in the study population. The increase in GDM disproportionately affected minoritized and marginalized groups. Public health policies and programs must address the negative impact of lockdown restrictions on health equity.

Key Points.

• The COVID-19 lockdown was associated with decreased GWG and increased GDM.

• No change in newborn BW was seen during the lockdown.

• Overall, the lockdown did not have a large clinical effect on these pregnancy outcomes.