Table 1 Baseline characteristics and secondary outcome of women undergoing stimulated in vitro fertilization (IVF) and frozen embryo transfer cycles (FET)

Age of women (years)

36 (33–37)

36 (34–38)

0.387

Body mass index (kg/m2)

21.94 (20.37–23.97)

22.72 (20.55–24.46)

0.08

Infertility cause

  Tubal

30

29

0.781

  Male

67

62

0.873

  Unexplained

37

35

0.833

  Anovulation

8

8

0.838

  Mixed

40

23

0.0544

  Others

7

14

0.070

Infertility duration (years)

4 (3–6)

4 (3–6)

0.360

Serum oestradiol on trigger day in stimulated IVF or LH surge in FET

960 (796–1197)

6425 (3543–10,212)

< 0.0001

Stage of embryos replaced

0.099

  Cleavage stage

152

116

  Blastocyst

37

55

Nulliparous

140 (74.1)

167 (97.7%)

< 0.0001

Nausea and vomiting in last pregnancy

0.567

  Yes

0 (0%)

0 (0%)

  No

56 (29.6%)

58 (33.9%)

  Not applicable

133 (70.4%)

113 (66.1%)

Secondary outcome

  Pregnancy Outcomes

0.506

  Miscarriage

23 (12.2%)

21(12.3%)

  Ectopic pregnancy

0 (0%)

2 (1.17%)

  Livebirth

166 (87.8%)

148 (86.6%)

  Mode of delivery

< 0.001

  Normal spontaneous delivery

49 (29.5%)

45 (30.4%)

  Assisted delivery

18 (10.8%)

20 (13.5%)

  Lower segment Caesarean section

99 (59.6%)

82 (55.4%)

  Assisted breech delivery

0 (0%)

1 (0.7%)

  Sex of baby

< 0.001

  Female

75 (45.2%)

83 (56.1%)

  Male

91 (54.8%)

65 (43.9%)

  Complications of pregnancy

  Small for gestational age

4 (2.4%)

3 (2.0%)

0.786

  Low birth weight

21(12.7%)

24 (16.2%)

0.439

  Preterm delivery

3(1.8%)

6 (4.1%)

0.255

  Pre-eclampsia and gestational hypertension

5 (3.0%)

4 (2.7%)

0.832

  Gestational diabetes

31 (18.7%)

23 (15.5%)

0.394

  Perinatal mortality

2 (1.2%)

5 (3.4%)

0.209

  Placenta praevia

2 (1.2%)

5 (3.4%)

0.209

  Cervical incompetence

0 (0%)

0 (0%)

0

  Birth weight (gram)

3060 (2770–3320)

3018 (2635–3245)

0.727