Is in vitro fertilization associated with preeclampsia? A propensity score matched study

Table 2 Characteristics of preeclampsia and blood pressure during mid- and late-pregnancy

		Eligible study sample (n = 3084)			Propensity score matched sample (n = 948)
		IVF group (n = 474)	Non-IVF group (n = 2610)	P value	IVF group (n = 474)	Non-IVF group (n = 474)	P value
Preeclampsia ^a
Prevalence	n (%)	15 (3.2)	31 (1.2)	0.003	15 (3.2)	7 (1.5)	0.27
Timing (among those with preeclampsia)
Early onset (<32 weeks of gestation)	n (%)	2 (13.3)	3 (9.7)	0.71	2 (13.3)	0 (0)	0.27
Late onset (≥32 weeks of gestation)	n (%)	13 (86.7)	28 (90.3)		13 (86.7)	7 (100)
Severity (among those with preeclampsia)
Mild	n (%)	7 (46.7)	14 (45.2)	0.92	7 (46.7)	3 (42.9)	0.27
Severe	n (%)	8 (53.3)	17 (54.8)		8 (53.3)	4 (57.1)
Blood pressure
SBP during mid-pregnancy^b	mmHg, mean (SD)	109.0 (9.6)	108.2 (9.7)	0.10	109.0 (9.6)	109.3 (10.1)	0.42
DBP during mid-pregnancy^b	mmHg, mean (SD)	64.5 (6.6)	62.9 (6.9)	<0.001	64.5 (6.6)	64.3 (7.3)	0.99
SBP during late-pregnancy^c	mmHg, mean (SD)	112.1 (9.6)	111.2 (9.7)	0.068	112.1 (9.6)	112.1 (9.0)	0.35
DBP during late-pregnancy^c	mmHg, mean (SD)	67.4 (6.7)	65.9 (7.0)	<0.001	67.4 (6.7)	67.1 (6.8)	0.69
Birth outcomes
Birth weight	g, mean (SD)	3042.7 (425.7)	2988.1 (408.0)	0.008	3042.7 (425.7)	3007.0 (414.0)	0.21
Gestational age	weeks, mean (SD)	39.2 (1.6)	39.1 (1.6)	0.15	39.2 (1.6)	39.2 (1.7)	0.77

^aPreeclampsia is considered severe if systolic blood pressure (BP) is ≥160 mmHg or diastolic BP is ≥110 mmHg on two occasions at least six hours apart while the patient is on bed rest, or if proteinuria is ≥2 g/24 hours or ≥3 on dipstick in two random urine samples collected at least four hours apart.
^bmid-pregnancy: 28-32 weeks of gestation.
^clate-pregnancy: 34-38 weeks of gestation.
IVF, in vitro fertilization; SD, standard deviation; SBP, systolic blood pressure; DBP, diastolic blood pressure.
Chi-squared or Fisher’s exact tests for categorical variables and t-tests for continuous variables were used for the whole study population. Conditional logistic regression for categorical variables and regression analysis using the fixed effect model for continuous variables were used in the propensity score matched sample.
Values in bold are significant at the p = 0.05 level.

ISSN: 1471-2393