The association between timing of initiation of antenatal care and stillbirths: a retrospective cohort study of pregnant women in Cape Town, South Africa

Table 5 Sensitivity analysis for stillbirths in women who were lost-to-follow-up

	Model 1	Model 2	Model 3	Model 4
	aOR (95% CI)	aOR (95% CI)	aOR (95% CI)	aOR (95% CI)
Number of observations	34,671	34,671	34,671	34,671
Number of stillbirths in women lost-to-follow up	0	28	140	279
Total number of stillbirths	119	147	259	398
Gestational age at first ANC visit (Continuous)	1.02 (0.99-1.05)	1.00 (0.98-1.03)	1.00 (0.98-1.02)	0.98 (0.96-0.99)^a
Gestational age at first ANC visit (Trimesters)
1 ^st Trimester (ref)	1.00	1.00	1.00	1.00
2 ^nd Trimester	0.87 (0.43-1.76)	0.81 (0.45-1.45)	0.82 (0.53-1.28)	0.60 (0.44-0.82)^a
3 ^rd Trimester	1.20 (0.58-2.47)	0.96 (0.52-1.78)	0.94 (0.59-1.50)	0.55 (0.39-0.78)^a

Models 1, 2, 3, and 4 display scenarios where the assumed stillbirth rate in women who were lost-to-follow-up are: 0 per 1,000, 4 per 1,000, 20 per 1,000, and 40 per 1,000, respectively. All models are adjusted for parity, education, mother’s age, race, and smoking status.
aOR, Adjusted Odds Ratio.
^aIndicates a significant aOR at 5% significance.

ISSN: 1471-2393