Table III.

Weight gain since age 17, waist-to-hip ratio (WHR), and time to pregnancy, by female BMI at baseline

	BMI < 25				BMI 25–29				BMI ≥ 30
	No.	Cycles	Adjusted modela		No.	Cycles	Adjusted modela		No.	Cycles	Adjusted modela
			FR	95% CI			FR	95% CI			FR	95% CI
Weight change since age 17 years (kg)
<−5	43	191	1.04	0.71–1.52	3	38	0.67	0.17–2.65	1	11	0.33	0.02–4.41
−5 to 4	340	1608	1.00	(ref.)	15	103	1.00	(ref.)	4	20	1.00	(ref.)
5–9	282	1540	0.90	0.75–1.08	42	261	1.01	0.50–2.05	6	21	0.69	0.13–3.72
10–14	124	682	0.88	0.69–1.11	57	268	1.05	0.53–2.11	15	111	0.38	0.09–1.72
≥15	38	238	0.78	0.53–1.15	63	384	0.86	0.44–1.68	97	740	0.35	0.09–1.43
WHR
<0.75	241	1334	1.00	(ref.)	24	175	1.00	(ref.)	9	56	1.00	(ref.)
0.75–0.79	174	1065	0.99	0.76–1.31	34	262	1.01	0.48–2.11	15	119	0.92	0.22–3.83
0.80–0.84	191	879	1.18	0.87–1.59	56	303	1.07	0.46–2.50	24	183	1.38	0.34–5.59
≥0.85	221	981	1.34	1.06–1.70	85	438	1.14	0.43–3.03	75	545	1.09	0.34–3.54

FR = fecundability ratio; CI = confidence interval; No. = number of pregnancies.

^aAdjusted for age, partner's age, cycle regularity, cycle length, physical activity, smoking, alcohol intake, parity and intercourse frequency.