. 2020 Jun 3;35(7):1685–1692. doi: 10.1093/humrep/deaa082

Table IV.

Frequency of pregnancies and relative risk of ectopic pregnancies between women with and without a benzodiazepine prescription, by exposure definition.

Benzodiazepine exposure definition	Had a benzodiazepine prescription		Did not have any benzodiazepine prescriptions		Risk difference^b (95% CI)	Relative risk (95% CI)
Benzodiazepine exposure definition	N	Events^a (Risk^b)	N	Events^a (risk^b)		Crude	IPT-weighted^b
Less strict^* definition	61 292	1555 (254)	1 673 376	29 584 (177)	77 (64, 90)	1.44 (1.36, 1.51)	1.27 (1.20, 1.34)^c
Stricter^** definition	13 813	354 (258)	1 673 376	29 584 (177)	81 (55, 108)	1.46 (1.32, 1.62)	1.54 (1.37, 1.73)^d

Abbreviations: IPT = inverse probability of treatment

^*At least one benzodiazepine prescription in the 90 days before conception

^**At least two benzodiazepine prescriptions in the 90 days before conception totaling at least 10 days supply, with at least one benzodiazepine prescription in the 30 days before conception

^aNumber of ectopic pregnancies

^bPer 10 000 pregnancies

^cSee Supplementary Table SX for unweighted and IPT-weighted standardized differences of baseline characteristics

^dSee Supplementary Table SXI for unweighted and IPT-weighted standardized differences of baseline characteristics