Reduction in spontaneous and iatrogenic preterm births in twin pregnancies during COVID-19 lockdown in Melbourne, Australia: a multicenter cohort study

Manno, Juliana M.; Marzan, Melvin B.; Rolnik, Daniel L.; Potenza, Stephanie; Pritchard, Natasha; Said, Joanne M.; Palmer, Kirsten R.; Whitehead, Clare L.; Sheehan, Penelope M.; Ford, Jolyon; Mol, Ben W.; Walker, Susan P.; Hui, Lisa

doi:10.1186/s12884-023-06137-9

Table 2 Primary and secondary outcomes for all pregnancies in the pre-pandemic, exposure 1 and 2 cohorts

From: Reduction in spontaneous and iatrogenic preterm births in twin pregnancies during COVID-19 lockdown in Melbourne, Australia: a multicenter cohort study

Outcomes	Pre-pandemic n = 1219		Exposure 1 n = 433		Exposure 2 n = 615		Exposure 1 aRR			Exposure 2 aRR
Outcomes	n	%	n	%	n	27%	aRR^a	95% CI	P value	aRR^a	95% CI	P value
Preterm birth < 37 wk
Total	833	68.3	273	63.1	438	71.2	0.92	0.87–0.98	0.01	1.03	0.98–1.09	0.19
Spontaneous	247	20.3	82	18.9	136	22.1	0.95	0.90–0.99	0.04	1.00	0.95–1.04	0.83
Iatrogenic	586	48.1	191	44.1	302	49.1	0.97	0.92–1.03	0.39	1.04	0.99–1.10	0.16
Preterm birth < 34 wk
Total	280	23.0	86	19.9	168	27.3	0.93	0.89–0.98	0.01	1.04	0.99–1.09	0.09
Spontaneous	129	10.6	45	10.4	72	11.7	0.97	0.94–1.01	0.15	1.01	0.98–1.04	0.65
Iatrogenic	151	12.4	41	9.5	96	15.6	0.96	0.92–1.00	0.05	1.03	1.00–1.07	0.09
Preterm birth < 28 wk
Total	58	4.8	23	5.3	44	7.2	1.00	0.97–1.03	0.95	1.03	1.01–1.05	0.04
Spontaneous	30	2.5	12	2.8	22	3.6	1.00	0.98–1.02	0.79	1.02	1.00–1.03	0.09
Iatrogenic	28	2.3	11	2.5	22	3.6	0.98	0.96–1.00	0.08	1.00	0.98–1.02	0.94
Preterm birth < 24 wk
Total	20	1.6	7	1.6	15	2.4	0.99	0.97–1.00	0.10	1.00	0.98–1.01	0.64
Iatrogenic	12	1.0	6	1.4	8	1.3	1.00	0.98–1.01	0.44	1.00	0.99–1.01	0.47
Spontaneous	8	0.7	1	0.2	7	0.8	0.99	0.98–1.00	0.10	1.00	0.99–1.01	0.88
Iatrogenic birth for suspected fetal compromise
Total	249	0.4	58	13.4	122	19.8	0.94	0.89–0.98	0.01	1.00	0.96–1.04	0.92
≥ 37 wk	53	13.7	11	6.9	27	15.3	0.94	0.88–1.01	0.07	1.02	0.96–1.09	0.54
< 37 wk	196	23.5	47	17.2	95	21.7	0.94	0.89–1.01	0.08	0.99	0.94–1.04	0.61
Mode of birth
Vaginal	361	29.6	112	25.9	180	29.3	0.93	0.88–0.98	0.01	0.96	0.92–1.01	0.12
Cesarean section after labor onset	413	33.9	145	33.5	235	38.2	0.97	0.92–1.03	0.30	1.03	0.98–1.08	0.32
Cesarean section with no labor	445	36.5	176	40.6	200	32.5	1.11	1.05–1.18	0.001	1.01	0.96–1.06	0.66
Pregnancy care indicators
First antenatal visit ≤ 12 wk	717	58.8	294	67.9	426	69.3	1.06	1.00–1.12	0.05	1.06	1.01–1.12	0.02
Severe PPH > 1000ml	129	10.6	40	9.2	66	10.7	0.96	0.92–0.99	0.02	0.98	0.95–1.01	0.23

aRR Adjusted risk ratio, CI Confidence interval, PPH Post-partum haemorrhage, wk Weeks
^aAdjusted for covariates of preterm birth including maternal age group, first measured BMI, region of birth, SEIFA, interpreter requirement, parity, smoking status and pertussis vaccination using multivariate log-binomial regression models. The log-binomial regression models used the ‘multiple imputations by chained equation’ (MICE) to account for missing data: missing or implausible for weight = 85 (3.76%); missing or implausible height = 15 (0.66%), smoking status = 0 (0%), need for interpreter variable = 0 (0%), maternal age = 6 (0.13%), BMI = 169 (7.34%), region of birth = 11 (0.49%), SEIFA = 35 (1.55%), sex = 1 (0.04%)

Back to article page

ISSN: 1471-2393

Contact us

Submission enquiries: bmcpregnancyandchildbirth@biomedcentral.com
General enquiries: ORSupport@springernature.com

BMC Pregnancy and Childbirth

Contact us