Short interpregnancy intervals and associated risk of preterm birth in Asians and Pacific Islanders

Purpose: The prevalence of short interpregnancy intervals (IPIs) and associated rates of preterm birth has been understudied in Asian and Pacific Islander populations. We sought to estimate rates of short IPI among Asian subgroups and Pacific Islanders and associated risk of preterm birth.

Materials and methods: For this retrospective cohort study, we linked records of women in California with a first birth in 1999-2000 and a second birth before 2005 with hospital discharge data. We used multivariate modeling to determine whether specific Asian ethnicities and Pacific Islanders were at greater risk of short IPI (<6 months, 6-18 months) and if a short IPI increased risk for preterm birth in these groups.

Results: Our sample included 189,931 women. In multivariable analyses, Asian subgroups and Pacific Islanders were more likely to have an IPI <6 months than were White women (Pacific Islanders: OR 3.31 (95%CI [2.7, 4.1]); Filipinas: OR 1.51 (95%CI [1.33, 1.71]); Southeast Asians: OR 1.93 (95%CI [1.73, 2.1]); East Asians: OR 1.65 (95%CI [1.48, 1.84]); other Asians: OR 2.04 (95%CI [1.70, 2.4])).

Conclusions: Asian and Pacific Islander women have higher rates of IPI <6 months, but this did not significantly increase their risk of preterm birth.