Table 2.

Cosinor analyses of DDH births in Indiana

	n	Periodicity	r 2	p value	M	A	ϕ	Month
All	424	7	0.70	0.005	33.61	11.45	122	Mar 13, Oct 12
VD	204	7	0.75	0.002	16.11	5.88	125	Mar 15, Oct 14
CS	183	7	0.69	0.005	14.38	5.86	117	Mar 10, Oct 9
Breech	125	8	0.57	0.023	9.92	3.19	44	Jan 30, Sep 30
Vertex	259	7	0.86	<0.001	20.23	9.00	132	Mar 19, Oct 18
Unilateral	281	7	0.71	0.004	22.36	7.05	118	Mar 11, Oct 10
Bilateral	140	8	0.43	0.079	10.74	4.30	100	Mar 9, Nov 7
Left	208	6	0.67	0.007	17.34	4.17	174	Mar 29, Sep 28
Right	72	7	0.54	0.032	5.61	2.72	110	Mar 6, Oct 5
Pavlik	260	7	0.61	0.014	20.39	8.46	132	Mar 19, Oct 18
Operative	126	10	0.56	0.025	10.30	2.16	340	Oct 15
Live births in Indiana	698,390	11	0.60	0.017	58,417.00	505.10	226	29-July

VD vaginal delivery, CS cesarean section, M mesor, A amplitude, ϕ acrophase, Month acrophase of cosinor analysis converted to month