Long-term significant seasonal differences in the numbers of new-borns with an orofacial cleft in the Czech Republic – a retrospective study

Table 2 Girls born during 1964–2000

Month		I	II	III	IV	V	VI	VII	VIII	IX	X	XI	XII
NC	Σ	207,032	198,352	230,452	229,166	230,680	216,559	218,629	207,749	201,606	192,596	182,260	189,343
	N	37	37	37	37	37	37	37	37	37	37	37	37
	x̄	5595.46	5360.86	6228.43	6193.68	6234.59	5852.95	5908.89	5614.84	5448.81	5205.30	4925.95	5117.38
	SE	196.73	192.24	230.57	229.77	223.85	196.62	192.30	191.31	183.63	177.38	172.90	181.12
CL	Σ	29	36	61	58	41	46	44	39	45	35	36	40
	N	37	37	37	37	37	37	37	37	37	37	37	37
	x̄	0.78	0.97	1.65	1.57	1.11	1.24	1.19	1.05	1.22	0.95	0.97	1.08
	SE	0.13	0.15	0.26	0.22	0.18	0.18	0.17	0.18	0.18	0.14	0.17	0.20
CLP	Σ	60	68	68	64	73	65	60	52	63	48	50	56
	N	37	37	37	37	37	37	37	37	37	37	37	37
	x̄	1.62	1.84	1.84	1.73	1.97	1.76	1.62	1.41	1.70	1.30	1.35	1.51
	SE	0.24	0.27	0.20	0.20	0.23	0.21	0.20	0.21	0.25	0.19	0.20	0.22
CP	Σ	98	96	107	104	101	98	111	91	91	93	84	92
	N	37	37	37	37	37	37	37	37	37	37	37	37
	x̄	2.65	2.59	2.89	2.81	2.73	2.65	3.00	2.46	2.46	2.51	2.27	2.49
	SE	0.25	0.30	0.31	0.32	0.31	0.28	0.24	0.28	0.28	0.25	0.24	0.30

Groups of girls: NC non-cleft control, CL cleft lip, CLP cleft lip and palate, CP cleft palate
Σ - total monthly number corresponding to all girls that born in a given month for 37 years; N – number of years; x̄ – mean monthly number of newborn girls; SE – standard error of the mean

ISSN: 1471-2393