Interpregnancy Weight Change Among Mothers of a Child with a Major Congenital Anomaly: A Danish Nationwide Cohort Study

Figures & data

Figure 1 Flow diagram of cohort derivation.

Table 1 Characteristics of the Mothers and Their First- and Second-Born Infants. All Data are Presented as a Number (%) Unless Otherwise Indicated

Characteristic	First Born Infant Affected by a Major Congenital Anomaly (N = 4035)	First Born Infant Not Affected by a Major Congenital Anomaly (N = 195,501)
Of the mother in the first pregnancy
Mean (SD) age at delivery, years	27.6 (4.4)	27.7 (4.2)
Mean (SD) weight at the first antenatal visit, kg	68 (14.4)	66.9 (13.4)
Mean (SD) BMI at the first antenatal visit, kg/m^2	24.1 (4.7)	23.7 (4.4)
BMI category, kg/m^2
Underweight: < 18.5	178 (4.4)	9117 (4.7)
Normal 18.5 to < 25	2450 (60.7)	124,342 (63.6)
Overweight: 25 to < 30	931 (23.1)	42,853 (21.9)
Obese: ≥ 30	476 (11.8)	19,189 (9.8)
Immigrant	470 (11.6)	21,674 (11.1)
Educational level^a
Basic education	826 (20.5)	35,007 (17.9)
High school	1643 (40.7)	81,358 (41.6)
Higher education	1255 (31.1)	65,111 (33.3)
Income quintile^b
1 (lowest)	774 (19.2)	35,623 (18.2)
2	628 (15.6)	31,705 (16.2)
3	700 (17.3)	32,348 (16.5)
4	841 (20.8)	40,472 (20.7)
5 (highest)	939 (23.3)	48,868 (25.0)
Marital status
Married/registered partnership	1083 (26.8)	51,347 (26.3)
Divorced	78 (1.9)	3489 (1.8)
Widow	–	91 (0.0)
Not married or unknown	2874 (71.2)	140,574 (71.9)
Medical history
Pre-pregnancy diabetes mellitus	34 (0.8)	997 (0.5)
Gestational diabetes mellitus	103 (2.6)	3890 (2.0)
Chronic hypertension	24 (0.6)	546 (0.3)
Gestational hypertension	294 (7.3)	10,881 (5.6)
Depression	40 (1.0)	1779 (0.9)
Smoking at the first antenatal visit^c	529 (13.1)	23,508 (12.0)
Of the first liveborn infant
Female^d	1487 (36.9)	94,998 (48.6)
Year of birth
2004–2007	1482 (36.7)	74,183 (37.9)
2008–2011	1389 (34.4)	71,031 (36.3)
2012 onward	1164 (28.8)	50,287 (25.7)
Gestational age at birth, weeks
37–42	3179 (78.8)	172,887 (88.4)
32–36	500 (12.4)	9491 (4.9)
28–31	116 (2.9)	896 (0.5)
23–27	59 (1.5)	392 (0.2)
42+	181 (4.5)	11,835 (6.1)
Birth weight, kg	3.2 (0.8)	3.4 (0.6)
Apgar score^e
< 7	139 (3.4)	1531 (0.8)
≥ 7	3840 (95.2)	192,779 (98.6)
Cumulative number of days hospitalized preceding the start of the second pregnancy
0–6	2166 (53.7)	184,482 (94.4)
7–30	1406 (34.8)	10,247 (5.2)
> 30+	463 (11.5)	772 (0.4)
Died preceding the start of the second pregnancy	35 (0.9)	67 (0.0)
Mean (SD) time interval between estimated date of conception in the first and second pregnancies, months	36.4 (17.9)	36.9 (17.6)
Of the second liveborn infant
Female^f	1961 (48.6)	94,950 (48.6)
Gestational age at birth, weeks
37–42	3735 (92.6)	184,034 (94.1)
32–36	171 (4.2)	5805 (3.0)
28–31	20 (0.5)	553 (0.3)
23–27	10 (0.2)	204 (0.1)
42+	99 (2.5)	4905 (2.5)
Birth weight, kg	3.5 (0.6)	3.6 (0.5)
Apgar score^g
< 7	23 (0.6)	981 (0.5)
≥ 7	3997 (99.1)	193,260 (98.9)
Major congenital anomaly	154 (3.8)	3662 (1.9)

Notes: ^aEducation unknown among 311 (7.7%) and 14,025 (7.2%), respectively. ^bIncome quintile unknown among 153 (3.8%) and 6485 (3.3%), respectively. ^cSmoking at the first antenatal visit unknown among 96 (2.4%) and 2791 (1.4%), respectively. ^dSex of the first liveborn infant unknown among 159 (3.9%) and 439 (0.2%), respectively. ^eAgpar score of first liveborn infant unknown among 56 (1.4%) and 1191 (0.6%), respectively. ^fSex of the second liveborn infant unknown among 8 (0.2%) and 581 (0.3%), respectively. ^gAgpar score of the second liveborn infant unknown among 15 (0.4%) and 1260 (0.6%), respectively.

Figure 2 Interpregnancy weight difference among mothers who ielivered an infants with vs without major congenital anomalies. Analyses stratified based on baseline BMI: underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5 to <25 kg/m²), overweight (BMI 25 to <30 kg/m²) or obesity (BMI ³ 30 kg/m²). Models adjusted for interpregnancy interval, maternal age, immigrant status, income, marital status, smoking status at the first pregnancy, gestational diabetes, chronic hypertension, preeclampsia/eclampsia and depression.

Figure 3 Interpregnancy weight difference among mothers who delivered an infant with multiorgan or single-organ major congenital anomalies vs without major congenital anomalies. Analyses stratified based on baseline BMI: underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5 to <25 kg/m²), overweight (BMI 25 to < 30 kg/m²) or obesity (BMI ³ 30 kg/m²). Models adjusted for interpregnancy interval, maternal age, immigrant status, income, marital status, smoking status at the first pregnancy, gestational diabetes, chronic hypertension, preeclampsia/eclampsia and depression.

Figure 4 Interpregnancy weight difference among mothers who delivered an infants with and without major congenital anomalies with varying total infant days of hospitalizations in the interpregnancy interval. Models adjusted for interpregnancy interval, maternal age, immigrant status, income, marital status, smoking status at the first pregnancy, gestational diabetes, chronic hypertension, preeclampsia/eclampsia and depression. Referent group = infants born without major congenital anomalies with total hospitalizations of 0–6 days.