Table 1.

Indian studies on prevalence of vitamin B12, folate deficiency, or hyperhomocysteinemia during pregnancy.

Sl. No.	Title/Author	Region	Time point	Findings
1	Iron, folate, and vitamin B12 stores among pregnant women in a rural area of Haryana State, India Pathak et al. (17)	Haryana (rural – North India)	≥28 week pregnancy	74.1%, 67.7%, 26.3%, of the women had low vitamin B12 (<200pg/ml~150pmol/L), ferritin (<12ng/ml), and folate (<3ng/ml), respectively. Concomitant deficiencies of iron, folate, and vitamin B12 occurred in 16.2% of the women
2	Low plasma vitamin B12 in pregnancy is associated with gestational ‘diabesity’ and later diabetes Krishnaveni et al. (18)	Mysore (Urban low socioeconomic status women – South India)	30 weeks gestation	In 774 women in third trimester, 43% had low B12 (<150pmol/L) and 4% had folate deficiency. Low B12 prevalence was 50.7% in Hindu mothers (predominantly vegetarian) and 35.6% in Muslim mothers (non-vegetarian).
3	Vitamin B12 and folate concentrations during pregnancy and insulin resistance in the offspring: the Pune Maternal Nutrition Study Yajnik et al. (19)	Pune (rural – West India)	18 and 28 week pregnancy	In ~600 women 60% had low B12 (<150 pmol/L), at 18 weeks with median concentrations of 135pmol/L. At 28 weeks 70% of mothers had low vitamin B12 (<150 pmol/l) median concentrations 122pmol/L, 90% had high MMA (>0.26 μmol/l) and 30% had raised tHcy concentrations (>10 μmol/l) Folate deficiency was seen in 1% women.
4	Vitamin B12 and folic acid supplementation and plasma total homocysteine concentrations in pregnant Indian women with low B12 and high folate status Katre et al. (20)	Pune (rural and urban – West India)	17 weeks pregnancy	In 200 pregnant women, B12 deficiency (<150pmol/L) seen in 80% rural and 64% urban women. Hyperhomocystenenia (>10 μmol/l) seen in 28% rural and 26% urban women
5&6	Vitamin B12 intake and status in early pregnancy among urban South Indian women Finkelstein et al. (21), Samuel et al. (22)	Bengaluru (urban low socioeconomic status women - South India)	First measurement at ≤14 weeks of gestation and at 2nd and 3rd trimester	In 366 pregnant women low vitamin B 12 concentration (<150pmol/L) was observed in 51.1% of the women, Elevated MMA (>0.26 µmol/l), elevated homocysteine (>10 µmol/l) and low erythrocyte folate (<283 nmol/l) were observed among 75.8, 43.3 and 22.2% of the women, respectively. In a subset of 77 women median plasma B12 concentrations was 150pmol/L in 1st and 2nd trimesters and fell to 139pmol/L in third trimester.
7	Imbalance of folic acid and vitamin B12 is associated with birth outcome: an Indian pregnant women study Gadgil et al. (23)	Pune (Hospital based sample – West India)	36 weeks of gestation	In 50 women coming for antenatal care, Vitamin B12 concentration was <150 pg/ml (~110pmol/L) in 35% women. 82% women showed a high folic acid concentration (above 3–12 ng/ml) Total homocysteine concentration was above 9.5 μmol/l in 39%.
8	A prospective study of maternal fatty acids, micronutrients and homocysteine and their association with birth outcome Wadhwani et al. (24)	Pune (Hospital based sample – West India)	1st measurement at 16-20 week pregnancy and subsequently at 28-30 weeks and at the time of labor.	In 109 women, plasma vitamin B12 level (<150 pg/ml) was 22.22%, 31.64% and 42.04% at the three time points. Plasma folate levels (<10 ng/mL) were 46.66%, 56.25% and 61.79% respectively Plasma homocysteine levels (>10 nmol L) were 7.77%, 7.5% and 22.47% respectively.