. Author manuscript; available in PMC: 2025 May 1.

Published in final edited form as: Obstet Gynecol. 2024 Mar 14;143(5):700–703. doi: 10.1097/AOG.0000000000005552

Table 1.

Incidence, relative risk, and adjusted hazard ratio of rapid repeat birth and substance exposed rapid repeat birth by child protection system removal

Subsequent births	No first month removal N = 5,488	First month removal N = 1,405
Repeat short interval births (within 200-463 days)
Follow up person months	84,397.73	21,558.33
Event	116	47
Incidence Rate^*	1.37	2.18
Crude Relative Risk (95% CI)	Reference	1.58 (1.33-2.21)
Adjusted Hazard Ratio (95% CI)†	Reference	1.61 (1.09-2.36)

Substance exposed repeat short interval births
Follow up person months	84,397.73	21,558.33
Event	28	22
Incidence Rate^*	0.33	1.02
Crude Relative Risk (95% CI)	Reference	3.06 (1.76-5.35)
Adjusted Hazard Ratio (95% CI)^†	Reference	3.17 (1.65-6.08)

Per 1,000 person months;

^†

Model adjusted for maternal race and ethnicity, maternal age, maternal education, insurance type, prior births, and documentation of paternity.