Association between COVID-19 lockdown measures and the incidence of iatrogenic versus spontaneous very preterm births in the Netherlands: a retrospective study

Table 1 Baseline characteristics of both cohorts

Characteristics	Cohort 2020	Cohort 2015–2018	p-value
	GA < 32 weeks	GA < 32 weeks
	N = 200 births	N = 829 births
Gestation age (GA) in days, mean (SD)	200.1 (16.6)	202.6 (14.7)	0.051
Multiple gestation, no (%)	37 (18.5)	138 (16.6)	0.53^a
Mode of delivery^b
Singletons			0.63
Vaginal, no (%)	80 (49.0)	314 (47.3)
Cesarean section, no (%)	82 (51.0)	350 (52.7)
Multiple gestation			0.73
Vaginal, no (%)	21 (56.8)	69 (53.5)
Cesarean section, no (%)	16 (43.2)	60 (46.5)
Sex			0.79
Male, no (%)	125 (53.0)	520 (54.6)
Female, no (%)	108 (45.8)	432 (45.4)
Birth weight in grams, mean (SD) ^c	1189 (410)	1214 (391)	0.62
Birthweight <5th percentile (Hoftiezer curve), no (%)^d	46 (19.3)	219 (23.0)	0.22

GA gestation age, SD standard deviation
^a Pearson Uncorrected Chi-square
^b missing N = 32, some multiple pregnancies delivered one child vaginally and the other by caesarean
^c missing N = 1
^d Calculated over the number of children with available birth weight N = 238 in 2020, N = 951 in 2015–2018

ISSN: 1471-2393