Other Direct Complications
Model Inputs \(\rightarrow\) Obstetric Complications \(\rightarrow\) Other Direct Complications
Overview
In addition to the major direct causes of maternal death included in the model, there also exist various other complications which pose mortality risks. While the risk of each individual cause is small, all together these ‘other direct’ causes form a substantial source of maternal morbidity and mortality.
Data
To examine reported maternal deaths due to other direct causes we obtained deaths by ICD-10 code from the WHO Mortality Database, a compilation of mortality data by age, sex, and cause of death, as reported annually by countries from their civil registration systems.[1]
We identified maternal deaths using the following ICD-10 codes:
| Code | Description |
|---|---|
| N96 | Habitual aborter |
| N98 | Complications associated with artificial fertilization |
| O00-O99 | Pregnancy, childbirth and the puerperium |
| 1087 | Summary code for O00-O99 Pregnancy, childbirth and the puerperium |
| 1088 | Summary code for O00-O07 Pregnancy with abortive outcome |
| 1089 | Summary code for O10-O92 Other direct obstetric deaths |
| 1090 | Summary code for O98-O99 Indirect obstetric deaths |
| 1091 | O95-O97 Remainder of pregnancy, childbirth and the puerperium |
We restricted the dataset to country/year estimates between 1995-2017 with non-zero maternal deaths, totalling 1484 observations from 114 countries. According to these data, ‘other direct’ causes accounted for nearly 20% of reported global maternal deaths. We also calculated the proportion of maternal deaths due to ‘other direct’ causes by income group (not enough data were available for low income countries). We see a gradient by income group, with a higher proportion of deaths due to ‘other direct’ causes in high income countries, likely because the risk of death from other major obstetric complications is lower.
We also calculated the distribution of the reported causes of death for ICD-10 codes included in ‘other direct’ maternal deaths:
| ICD-10 | Description | Percent (%) |
|---|---|---|
| O88 | Obstetric embolism | 24.0 |
| O26 | Maternal care for other conditions predominantly related to pregnancy | 14.4 |
| O75 | Other complications of labour and delivery, not elsewhere classified | 14.1 |
| O90 | Complications of the puerperium, not elsewhere classified | 13.2 |
| O95 | Obstetric death of unspecified cause | 13.0 |
| O36 | Maternal care for other known or suspected fetal problems | 3.9 |
| O41 | Other disorders of amniotic fluid and membranes | 2.4 |
| O73 | Retained placenta and membranes, without haemorrhage | 2.3 |
| O22 | Venous complications and haemorrhoids in pregnancy | 2.0 |
| O87 | Venous complications and haemorrhoids in the puerperium | 1.9 |
| O74 | Complications of anaesthesia during labour and delivery | 1.5 |
| O43 | Placental disorders | 1.2 |
| O42 | Premature rupture of membranes | 1.0 |
| O34 | Maternal care for known or suspected abnormality of pelvic organs | 0.8 |
| O21 | Excessive vomiting in pregnancy | 0.6 |
| O29 | Complications of anaesthesia during pregnancy | 0.5 |
| O60 | Preterm labour and delivery | 0.5 |
| O89 | Complications of anaesthesia during the puerperium | 0.4 |
| O30 | Multiple gestation | 0.4 |
| O68 | Labour and delivery complicated by fetal stress [distress] | 0.4 |
| O70 | Perineal laceration during delivery | 0.3 |
| O69 | Labour and delivery complicated by umbilical cord complications | 0.2 |
| O40 | Polyhydramnios | 0.2 |
| O48 | Prolonged pregnancy | 0.1 |
| O35 | Maternal care for known or suspected fetal abnormality and damage | 0.1 |
| O31 | Complications specific to multiple gestation | 0.1 |
| O61 | Failed induction of labour | 0.1 |
| O47 | False labour | 0.1 |
| N98 | Complications associated with artificial fertilization | 0.1 |
| O92 | Other disorders of breast and lactation associated with childbirth | 0.1 |
| O28 | Abnormal findings on antenatal screening of mother | <0.1 |
We see that nearly 25% of reported ‘other direct’ maternal deaths are due to obstetric embolism, 55% are due to ‘other conditions’ or unspecified causes, and 20% are due to various remaining causes. While it is the largest cause of ‘other direct’ maternal deaths, obstetric embolism is rare - a study of deliveries in the US from 1980 to 2005 estimated that it occurs in around 10 per 100,000 births,[2] with estimated case fatality rates varying between 13% to 26%.[3,4] A study of in-hospital maternal deaths in Canada found similar estimates, with obstetric embolism associated with 1.8 maternal deaths per 100,000 deliveries.[5]
Parameters
Because the causes of ‘other direct’ maternal death are relatively rare individually, we model them as a group. Given that the largest single cause, obstetric embolism, is estimated to occur in about 1 per 10,000 deliveries, and accounts for about 25% of deaths from other direct causes, we set (fairly wide) priors for incidence of other direct causes around 4 per 10,000 births. While some causes of death may be related to clinical interventions at facilities (e.g. anaesthesia), given the relatively small number of potential iatrogenic deaths, for simplicity we assume that the incidence of other direct causes is non-differential by delivery site. However, as many of these causes are mainly treated with supportive care, we do not model specific clinical interventions, but simulate mortality risks conditional on a woman’s delivery site. We assume that case fatality rates decrease with higher level delivery sites and enforce these constraints when sampling parameters (Home > Home-SBA > non-EmOC > BEmOC > CEmOC).
Priors
Model Implementation
Although some complications included in ‘other direct’ deaths may occur earlier in pregnancy, for simplicity we model the risk of these complications at the time of delivery. If a complication occurs, the risk of mortality is simulated based on a woman’s delivery site (and quality of care).
References
- World Health Organization. WHO Mortality Database - Last updated: 15 December 2019. Available at: https://www.who.int/healthinfo/mortality_data/en/
- Stein PD, Matta F, Yaekoub AY. Incidence of amniotic fluid embolism: relation to cesarean section and to age. J Womens Health (Larchmt) 2009; 18(3): 327-9. DOI: https://doi.org/10.1089/jwh.2008.0974
- Kramer MS, Rouleau J, Baskett TF, Joseph KS, Maternal Health Study Group of the Canadian Perinatal Surveillance System. Amniotic-fluid embolism and medical induction of labour: a retrospective, population-based cohort study. Lancet 2006; 368(9545): 1444-8. DOI: https://doi.org/10.1016/s0140-6736(06)69607-4
- Gilbert WM, Danielsen B. Amniotic fluid embolism: decreased mortality in a population-based study. Obstet Gynecol 1999; 93: 973–77. https://doi.org/10.1016/s0029-7844(99)00004-6
- Lisonkova S, Liu S, Bartholomew S, Liston RM, Joseph KS, Maternal Health Study Group of the Canadian Perinatal Surveillance System. Temporal trends in maternal mortality in Canada II: estimates based on hospitalization data. J Obstet Gynaecol Can 2011; 33(10): 1020-30. DOI: https://doi.org/10.1016/s1701-2163(16)35051-4
GMatH (Global Maternal Health) Model - Last updated: 28 November 2022
© Copyright 2020-2022 Zachary J. Ward
zward@hsph.harvard.edu