Table 4.
Risk factors associated with miscarriage in women with a single first-trimester episode of Plasmodium vivax or Plasmodium falciparum
| Miscarriage (313) | Delivery (595) | Unadjusted odds ratio (95% CI; p value) | Adjusted odds ratio (95% CI; p value)* | ||
|---|---|---|---|---|---|
| Malaria symptoms† | |||||
| Asymptomatic | 39% (100) | 56% (211) | Reference group | Reference group | |
| Symptomatic | 61% (154) | 44% (169) | 1·92 (1·39–2·66; p=0·0001) | 1·42 (0·95–2·14; p=0·089) | |
| Severity of malaria‡ | |||||
| Uncomplicated | 95% (297) | 98% (580) | Reference group | Reference group | |
| Severe or hyperparasitaemic | 5% (14) | 2% (10) | 2·73 (1·20–6·23; p=0·017) | 3·63 (1·15–11·46; p=0·028) | |
| Species | |||||
| Plasmodium falciparum | 52% (163) | 56% (333) | Reference group | Not included | |
| Plasmodium vivax | 48% (150) | 44% (262) | 1·17 (0·89–1·54; p=0·263) | Not included | |
| Pregnancy | |||||
| Women in their first pregnancy | 25% (78) | 28% (169) | Reference group | Not included | |
| Women who have had more than one pregnancy§ | 75% (235) | 72% (425) | 1·20 (0·88–1·64; p=0·256) | Not included | |
| Smoking¶ | |||||
| Non-smoker | 51% (122) | 71% (252) | Reference group | Reference group | |
| Smoker | 49% (118) | 29% (104) | 2·34 (1·67–3·30; p<0·0001) | 2·08 (1·43–3·02; p=0·0007) | |
| Age | |||||
| 13–20 years | 27% (84) | 31% (187) | Reference group | Reference group | |
| 21–25 years | 17% (54) | 28% (166) | 0·72 (0·49–1·08; p=0·114) | 0·78 (0·47–1·29; p=0·333) | |
| 26–30 years | 21% (66) | 20% (120) | 1·22 (0·82–1·82; p=0·316) | 1·30 (0·78–2·15; p=0·318) | |
| ≥31 years | 35% (109) | 21% (122) | 1·99 (1·38–2·86; p=0·0002) | 1·85 (1·16–2·96; p=0·010) | |
| Number of previous miscarriages‖ | |||||
| None | 62% (194) | 68% (406) | Reference group | Not included | |
| One | 25% (79) | 21% (126) | 1·31 (0·94–1·82; p=0·106) | Not included | |
| Two or more | 12% (38) | 10% (62) | 1·28 (0·83–1·99; p=0·266) | Not included | |
| Non-malaria febrile illness in the first trimester | |||||
| No | 97% (305) | 99% (590) | Reference group | Not included | |
| Yes | 3% (8) | 1% (5) | 3·10 (1·00–9·54; p=0·049) | ||
| Calculated estimated gestational age at malaria episode, weeks (median [IQR]) | 8·0 (5·7–10·5)†† | 10·2 (7·6–12·3)†† | 0·88 (0·85–0·92; p<0·0001) | 0·86 (0·81–0·91; p<0·0001) | |
| Parasitaemia, μL (geometric mean [95% CI; number of women])** | 1020 (726–1432; 262)‡‡ | 300 (238–378; 413)‡‡ | 1·52 (1·32–1·75; p<0·0001)§§ | 1·49 (1·25–1·78; p<0·0001)§§ | |
Data are unadjusted or adjusted odds ratio (95% CI).
The variables malaria (asymptomatic or symptomatic), severity of malaria, and parasitaemia were fitted in separate models because of collinearity, with each model adjusting for age, smoking, and calculated estimated gestational age at malaria episode.
Data missing for 59 patients in the miscarriage group and 215 in the delivery group.
Data missing for two patients in the miscarriage group and five in the delivery group.
Data missing for one patient in the delivery group.
Data missing for 73 patients in the miscarriage group and 239 in the delivery group.
Data missing for two patients in the miscarriage group and one in the delivery group.
Data missing for 51 patients in the miscarriage group and 182 in the delivery group.
Data are median (IQR).
Data are geometric mean (95% CI; number of women).
Relative change in odds for miscarriage associated with a ten-fold increase in parasitaemia.