Table 4 Distribution of methemoglobin levels by follow up period

Time 1

(Enrollment)^a

357

0.74 (0.48)

0.80

0.1-2.2

2

Time 2

(around 20 weeks)

317

0.67 (0.52)

0.60

0.1-3.6

3

Time 3

(around 28 weeks)

316

0.58 (0.46)

0.60

0.1-2.1

2

Time 4

(around 36 weeks)

304

0.51 (0.46)

0.50

0.1-2.2

2

Time 5

(day of delivery)

300

0.42 (0.47)

0.33

0.1-2.3

2

Time 6

(2-4 weeks postpartum)

295

0.39 (0.51)

0.28

0.1-3.0

5