Table 4.

Stability of Mean Hormone Concentrations Across Subsequent Pregnancies

Status	Hormone	N	F-statistic	DF	Adjusted R2	P
Pregnancy	ACTH	19	23.75	1,17	0.558	.00a
	pCRH	18	4.43	1,16	0.168	.05b
	Cortisol	16	8.50	1,14	0.333	.01c
	Estradiol	18	6.97	1,16	0.260	.02c
	Progesterone	18	16.34	1,16	0.474	.00a
Post-partum	ACTH	20	0.67	4,15	−0.075	.41 (ns)
	Cortisol	22	0.68	4,14	−0.077	.29 (ns)

Abbreviations: DF, degrees of freedom; ns, not significant.

Regression analyses measure the proportion of variance in PREG 2 hormone levels attributable to variance in PREG 1 hormone levels. Cortisol data were residualized by time of day at collection.

Postpartum models control for breastfeeding, resumption of menses, and hormonal contraceptive use. For the null postpartum models, the negative adjusted R² values are interpretable as zero.

P < .10 are in bold. See Supplemental Tables 2 and 3 for model details.

^aP < .001.

^bP < .10.

^cP < .05.

^dP < .01.