Table 1.

Summary of LTG registries findings

REGISTRY DETAILS	REGION	INCLUSI ON PERIOD	TOTAL NUMBER OF PREGNANCY OUTCOMES	MALFORMATION RATES OF LTG MONOTHERAPY	MALFORMATION RATES OF LTG + VPA POLYTHERAPY	COMMENTS
GlaxoSmithKline International Lamotrigine Pregnancy Registry Interim Report5	38 reporting countries	September 1992–March 2005	1246	2.8% (95% CI, 1.8%–4.4%)(n = 707)	11.8% (95% CI, 6.8%–19.3%)(n = 119)	87 retrospectively reported outcomes involving birth defects
UK Epilepsy and Pregnancy Register3	United Kingdom	1996–2005	3607	3.2% (95% CI, 2.1%–4.9%) for all LTG monotherapies(n = 647); 3.2% (95% CI, 2.1%–4.9%) for LTG doses of 200 mg/d or lower; 5.4% (95% CI, 3.3%–8.7%) for LTG doses higher than 200 mg/d	9.6%(95% CI, 5.7%–15.7%)	Positive dose-response relationship for malformations in LTG monotherapy; malformation rates in LTG monotherapy at doses higher than 200 mg/d are not statistically different from expectant mothers taking VPA at 1000 mg/d or less Potential effect should be considered in future studies
Swedish Medical Birth Registry5,6	Sweden	1995–2004	>1300	4.8% (95% CI, 2.5%–8.3%)(n = 248)	27% (n = 30)	No consistent malformation pattern
Australian Pregnancy Registry4	Australia	1999–December 2003	565	None reported(n = 61)		4 fetal malformations were observed in LTG polytherapy (n = 70), corresponding to 5.71% incidence rate; all 4 cases of LTG polytherapy with fetal malformations were using LTG with high doses of VPA (more than 1100 mg/d), while those treated with LTG combined with low VPA doses exhibited no fetal malformations
North American Antiepileptic Drug Pregnancy Registry7	North America	1997–January 2006	564	2.7% (95% CI, 1.5%–4.3%)(n = 564)		5 infants (0.89%) had oral clefts; potential increased risk for non-syndromic cleft palate
Meador and colleagues8	United States and United Kingdom	October 1999–February 2004	333	1.02% (95% CI, 0.03%–5.6%)(n = 98)

CI—confidence interval, LTG—lamotrigine, VPA—valporic acid.