Factors associated with short interpregnancy interval in women who plan postpartum LARC: a retrospective study

Pregnancies conceived after a short interpregnancy interval (IPI), within 18 months of delivery, and unintended pregnancies are both associated with health risks. We studied risk factors for conception after a short IPI among postpartum women who plan long-acting reversible contraception (LARC).

A retrospective review of a cohort of women who delivered at University of Illinois Hospital from 2005 to 2010 and were discharged with a plan for interval LARC was performed. Outcomes were (1) attendance at a postpartum visit (PPV), (2) LARC placement (3) and conception after a short IPI. We compared variables using chi-squared test, Student's t tests and multivariable logistic regression.

Of 3548 women, 62.0% attended a PPV, 36.5% received LARC and 11.4% conceived after a short IPI. After logistic regression, women who were multiparous [odds ratio (OR) 0.77, 95% confidence interval (CI) 0.65-0.91] or chose a temporary contraceptive "bridge" to LARC (OR 0.74, 95% CI 0.58-0.94) were less likely to attend their PPV. Women who missed their PPV (OR 0.06, 95% CI 0.05-0.08) or chose a bridge (OR 0.66, 95% CI 0.50-0.88) were less likely to receive LARC. Finally, women who did not receive LARC (OR 4.8, 95% CI 3.50-6.70), were multiparous (OR 1.69, 95% CI 1.32-2.15) or teenaged (OR 2.12, 95% CI 1.61-2.79) were more likely to conceive after a short IPI.

Women who receive postpartum LARC are less likely to become pregnant after a short IPI. Missing the PPV, multiparity and plan for a contraceptive bridge may all contribute to a patient not receiving planned LARC.

Efforts to decrease unintended pregnancy after a short IPI should focus on decreasing barriers to planned postpartum LARC. Provision of temporary bridge contraception until interval LARC may not mitigate the significant barriers associated with interval postpartum placement protocols.