The moderating role of depression in the association between hypertension during pregnancy and birth outcomes

Figures & data

Figure 1. Exclusion criteria for sample.

Table 1. Characteristics of study sample by hypertension status (unweighted n = 68,052).

Characteristics	Hypertension during pregnancy Weighted % (95% CI)		p-value*
	Yes (11.7%)	No (88.3%)
Maternal age			<0.01
<20 (years)	6.0 (5.2, 6.9)	4.2 (3.9, 4.4)
20–29	47.4 (45.8, 49.0)	47.8 (47.2, 48.4)
30–34	27.5 (26.1, 28.9)	30.1 (29.6, 30.7)
≥35	19.1 (17.9, 20.4)	17.9 (17.5, 18.4)
Race			<0.01
White	67.1 (65.6, 68.5)	69.9 (69.4, 70.4)
Black	20.9 (19.6, 22.2)	14.2 (13.8, 14.6)
Asian	3.1 (2.7, 3.6)	6.3 (6.1, 6.6)
Other nonwhite	5.3 (4.7, 6.0)	6.7 (6.4, 7.0)
Mixed race	3.6 (3.1, 4.2)	3.0 (2.8, 3.2)
Education level			<0.01
Less than high school	12.4 (11.4, 13.4)	12.2 (11.8, 12.6)
High school graduate	27.3 (25.9, 28.9)	23.3 (22.7, 23.8)
College and above	60.3 (58.7, 61.9)	64.5 (63.9, 65.1)
Annual total household income			<0.01
≤$20,000	32.1 (30.6, 33.7)	27.2 (26.7, 27.8)
$20,000–$40,000	21.2 (19.8, 22.6)	20.7 (20.1, 21.2)
>$40,000	46.7 (45.1, 48.4)	52.1 (51.5, 52.7)
BMI			<0.01
Underweight or normal weight	33.3 (31.8, 34.9)	52.8 (52.2, 53.4)
Overweight	26.4 (25.0, 27.9)	25.2 (24.7, 25.8)
Obesity	40.3 (38.7, 41.9)	22.0 (21.5, 22.5)
Weight gain during pregnancy			<0.01
Meet recommendation	22.4 (21.1, 23.7)	31.0 (30.5, 31.6)
Under recommendation	24.2 (22.8, 25.5)	27.1 (26.5, 27.6)
Exceed recommendation	53.5 (51.9, 55.1)	41.9 (41.3, 42.5)
Previous preterm births			<0.01
No	95.3 (94.7, 95.9)	96.8 (96.6, 97.0)
Yes	4.7 (4.1, 5.3)	3.2 (3.0, 3.4)
Insurance type			<0.01
Private/ACA**	46.2 (44.5, 47.8)	50.1 (49.4, 50.7)
Medicaid or other government insurance only	38.9 (37.3, 40.5)	35.2 (34.6, 35.8)
Other insurance	4.6 (4.0, 5.4)	5.2 (4.9, 5.5)
Medicaid and other insurance	8.6 (7.7, 9.6)	7.2 (6.9, 7.6)
No insurance	1.7 (1.4, 2.2)	2.3 (2.1, 2.5)
Diabetes during pregnancy			<0.01
No	82.5 (81.3, 83.7)	92.3 (92.0, 92.6)
Yes	17.5 (16.3, 18.7)	7.7 (7.4, 8.0)
Smoking in the last 3 months of pregnancy			<0.01
No	90.0 (89.0, 91.0)	92.1 (91.7, 92.4)
Yes	10.0 (9.0, 11.0)	7.9 (7.6, 8.3)
Infant sex			0.63
Male	51.4 (49.8, 53.0)	51.0 (50.4, 51.6)
Female	48.6 (47.0, 50.2)	49.0 (48.4, 49.6)
Prenatal care adequacy			<0.01
Inadequate	12.2 (11.2, 13.3)	11.7 (11.4, 12.2)
Intermediate	7.8 (7.0, 8.7)	11.3 (11.0, 11.7)
Adequate	34.7 (33.1, 36.3)	47.8 (47.2, 48.4)
Adequate plus	45.3 (43.7, 46.9)	29.1 (28.6, 29.7)
Visit for depression or anxiety 12 months before pregnancy			<0.01
No	90.5 (89.6, 91.4)	92.8 (92.4, 93.1)
Yes	9.5 (8.6, 10.4)	7.2 (6.9, 7.6)
Depression during pregnancy			<0.01
No	78.5 (77.2, 79.8)	89.6 (89.2, 89.9)
Yes	21.5 (20.2, 22.8)	10.4 (10.1, 10.8)

*P-value for Rao-Scott chi-square test.

**Affordable Care Act.

Table 2. Interaction between hypertension and depression during pregnancy on the risk of preterm birth (PTB) and low birth weight (LBW), PRAMS, 2016–2018 (n = 68,052).

Birth outcomes	PTB			LBW
	No Depression	Depression	Effect of depression within the strata of hypertension	No Depression	Depression	Effect of depression within the strata of hypertension
	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P
No Hypertension	1.00 (Reference)	1.29 (1.13,1.48); 0.0003	1.29 (1.13,1.48); 0.0003	1.00 (Reference)	1.45 (1.21, 1.73); <0.01	1.45 (1.21, 1.73); <0.01
Hypertension	2.58 (2.34,2.83); <0.01	2.04 (1.73,2.42); <0.01	0.79 (0.66,0.95); 0.01	4.03 (3.59, 4.54); <0.01	2.84 (2.27, 3.56); <0.01	0.70 (0.56, 0.88); 0.002
Effect of hypertension within the strata of depression	2.58 (2.34,2.83); <0.01	1.58 (1.30,1.92); <0.01		4.03 (3.59, 4.54); <0.01	1.96 (1.54, 2.50); <0.01

*Adjusted risk ratio and 95% confidence interval.

**Analysis adjusted for maternal age, race, education level, annual total household income, BMI, weight gain during pregnancy, previous preterm births, insurance type, diabetes during pregnancy, smoking in the last 3 months of pregnancy, infant sex, prenatal care adequacy, visit for depression or anxiety 12 months before pregnancy.

Measure of interaction on additive scale for PTB: RERI (95% CI) = −0.83 (−1.24, −0.41); P = 1.00

Measure of interaction on multiplicative scale for PTB: ratio of RRs (95% CI) = 0.61 (0.50, 0.76); P < 0.01.

Measure of interaction on additive scale for LBW: RERI (95% CI) = −1.64 (−2.35, −0.93); P = 1.00

Measure of interaction on multiplicative scale for LBW: ratio of RRs (95% CI) = 0.49 (0.37, 0.63); P < 0.01.

Table 3. Interaction between hypertension and depression during pregnancy on the risk of small-for-gestational-age (SGA) and large-for-gestational-age (LGA), PRAMS, 2016–2018 (n = 68,052).

Birth outcomes	SGA			LGA
	No Depression	Depression	Effect of depression within the strata of hypertension	No Depression	Depression	Effect of depression within the strata of hypertension
	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P	RR (95% CI)^*,**; P
No Hypertension	1.00 (Reference)	1.10 (0.97, 1.24); 0.15	1.10 (0.97, 1.24); 0.15	1.00 (Reference)	0.98 (0.84, 1.13); 0.76	0.98 (0.84, 1.13); 0.76
Hypertension	1.50 (1.34, 1.67); <0.01	1.39 (1.13, 1.71); 0.002	0.93 (0.75, 1.16); 0.52	0.84 (0.74, 0.96); 0.01	0.90 (0.70, 1.15); 0.41	1.07 (0.82, 1.40); 0.64
Effect of hypertension within the strata of depression	1.50 (1.34, 1.67); <0.01	1.27 (1.02, 1.57); 0.03		0.84 (0.74, 0.96); 0.01	0.92 (0.70, 1.21); 0.57

*Adjusted risk ratio and 95% confidence interval.

**Analysis adjusted for maternal age, race, education level, annual total household income, BMI, weight gain during pregnancy, previous preterm births, insurance type, diabetes during pregnancy, smoking in the last 3 months of pregnancy, infant sex, prenatal care adequacy, visit for depression or anxiety 12 months before pregnancy.

Measure of interaction on additive scale for SGA: RERI (95% CI) = −0.20 (−0.53, 0.12); P = 0.89

Measure of interaction on multiplicative scale for SGA: ratio of RRs (95% CI) = 0.85 (0.67, 1.08); P = 0.17.

Measure of interaction on additive scale for LGA: RERI (95% CI) = 0.08 (−0.19, 0.36); P = 0.28

Measure of interaction on multiplicative scale for LGA: ratio of RRs (95% CI) = 1.10 (0.81, 1.48); P = 0.55.

Table 4. Effect of hypertension during pregnancy within the strata of depression during pregnancy comparing complete-case data and multiply-imputed data.

Birth outcomes	Complete-case data (n = 51,607)		Multiply-imputed data (n = 68,052)
	Depressed	Not Depressed	Depressed	Not Depressed
	aRR(95%CI)^*,**		aRR(95%CI)^*,**
Preterm birth	1.59 (1.31,1.92)	2.59 (2.35,2.85)	1.58 (1.30,1.92)	2.58 (2.34,2.83)
Low birth weight	1.98 (1.55,2.53)	4.08 (3.62,4.58)	1.96 (1.54, 2.50)	4.03 (3.59, 4.54)
Small for gestational age	1.27 (1.02,1.58)	1.50 (1.34,1.67)	1.27 (1.02, 1.57)	1.50 (1.34, 1.67)
Large for gestational age	0.91 (0.69,1.20)	0.84 (0.74,0.96)	0.92 (0.70, 1.21)	0.84 (0.74, 0.96)

*Adjusted risk ratio and 95% confidence interval.

**Analysis adjusted for maternal age, race, education level, annual total household income, BMI, weight gain during pregnancy, previous preterm births, insurance type, diabetes during pregnancy, smoking in the last 3 months of pregnancy, infant sex, prenatal care adequacy, visit for depression or anxiety 12 months before pregnancy.

Data availability statement

The data that support the findings of this study are openly available via a data application to PRAMS at https://www.cdc.gov/prams/prams-data/researchers.htm.