Objective
We examined neonatal mortality in relation to birth settings and birth attendants in the United States from 2006 through 2009.
Study Design
Data from the Centers for Disease Control and Prevention–linked birth and infant death dataset in the United States from 2006 through 2009 were used to assess early and total neonatal mortality for singleton, vertex, and term births without congenital malformations delivered by midwives and physicians in the hospital and midwives and others out of the hospital. Deliveries by hospital midwives served as the reference.
Results
Midwife home births had a significantly higher total neonatal mortality risk than deliveries by hospital midwives (1.26 per 1000 births; relative risk [RR], 3.87 vs 0.32 per 1000; P < .001). Midwife home births of 41 weeks or longer (1.84 per 1000; RR, 6.76 vs 0.27 per 1000; P < .001) and midwife home births of women with a first birth (2.19 per 1000; RR, 6.74 vs 0.33 per 1000; P < .001) had significantly higher risks of total neonatal mortality than deliveries by hospital midwives. In midwife home births, neonatal mortality for first births was twice that of subsequent births (2.19 vs 0.96 per 1000; P < .001). Similar results were observed for early neonatal mortality. The excess total neonatal mortality for midwife home births compared with midwife hospital births was 9.32 per 10,000 births, and the excess early neonatal mortality was 7.89 per 10,000 births.
Conclusion
Our study shows a significantly increased total and early neonatal mortality for home births and even higher risks for women of 41 weeks or longer and women having a first birth. These significantly increased risks of neonatal mortality in home births must be disclosed by all obstetric practitioners to all pregnant women who express an interest in such births.
Despite the increase in home births in the United States over the last decade, the safety of home births has remained controversial. In our previous publication using the US natality data, we reported that home birth has an increased relative risk of 5 minute Apgar scores of zero and of seizures and other adverse neurological outcomes. Although a 5 minute Apgar score of zero is related to neonatal mortality, the linked birth/infant datasets (for live births and infant deaths) allow for the direct assessment of neonatal mortality relative to birth setting and attendant.
The purpose of this study therefore was to examine early, total, and excess neonatal mortality rates for singleton term births without congenital malformations by birth setting and birth attendant (hospital physician, hospital midwife, freestanding birth center, midwife, home midwife, and other for home births).
Materials and Methods
The 1989 revision of the US Standard Certificate of Live Birth provides additional detail for out-of-hospital births and makes it possible to distinguish among out-of-hospital births at home, in a birthing center, or other specified location. In contrast to the birth certificate files, which provide information on delivery, it is necessary to go to the Centers for Disease Control and Prevention (CDC)–linked birth/infant death dataset (for live births and infant deaths) to analyze neonatal mortality. This dataset (linked file) is generally the preferred source for infant and neonatal mortality in the United States.
It contains detailed information for the approximately 4 million births in the United States each year, including birth setting, birth attendant, and neonatal mortality. Period-linked files use all births in a year as the denominator and all deaths in a year as the numerator, regardless of when the birth occurred (eg, if the birth was in late 2008, then neonatal death could have been 2008 or 2009 but counted in the 2008 numerator only if the death occurred in 2008).
The 2006-2009 period-linked birth/infant deaths dataset was analyzed to examine early (deaths <7 days of life) and total (deaths <28 days of life) neonatal mortality in term singleton births (≥37 weeks and newborn weight of ≥2500 g) without documented congenital malformations by birth setting (hospital, birthing center, home) and provider: hospital midwife (certified nurse midwives [CNMs] and other midwife [MW]; hospital MW), hospital physician (MD or DO), free-standing birthing center midwife (CNM and other MW), home midwife (CNM and other MW, home MW), home other (including emergency situations, such as unattended births and “any other person delivering the baby, such as a husband or family member, emergency medical technician, or taxi driver”).
Total neonatal mortality (tNNM) is defined as the death of a live-born neonate before 28 days of life, and early neonatal mortality (eNNM) is defined as neonatal death before 7 days of life. We also examined the relative risks associated with delivery by provider and setting compared with hospital midwives. Excess neonatal mortality is defined as the increased number of neonatal deaths per 10,000 births by provider and setting, using hospital-based midwife deliveries as the reference group. Data on patient characteristics included parity, race and ethnicity, maternal age, and clinical factors such as neonatal weight and weeks of gestation at delivery.
We excluded infants if they met any of the following criteria: birth attendant type was not recorded; birth place was anywhere else but the hospital, home, or freestanding birthing center, or not recorded; gestational age was less than 37 weeks or not recorded; birthweight was less than 2500 g or not recorded; multiple gestations; any congenital anomaly, Down syndrome, or other chromosomal disorder was confirmed or pending; and a resident of a foreign country.
Because nonidentifiable data from a publicly available dataset were used, our study was not considered human subjects research and did not require review by the Weill Medical College of Cornell University Institutional Review Board.
Analysis of data
We analyzed tNNM (deaths <28 days of age) and eNNM (deaths <7 days of age). We computed relative risks (RRs) for all patients with a first birth (para = 0) and with a second or higher order birth (para of ≥1), and for term and postterm (≥41 weeks) pregnancies. Hospital midwives (hospital MW) included both CNMs and other midwives and served as the reference group for the estimation of early, total, and excess neonatal mortality. A free-standing birthing center midwife (CNM and other MW) and home midwives (home MW) include both CNMs and other midwives. Home ‘others’ includes others identified by the CDC database as attending home births, including family members, emergency medical service, or police, and taxi drivers as well as unattended births.
Data were extracted using SAS version 9.3 (SAS Institute, Cary, NC) and compiled in Excel (Microsoft, Redmond, WA). The RRs and 95% confidence intervals were computed in SAS version 9.3 (SAS Institute). Excess mortality was computed in OpenEpi.
Results
Table 1 shows the characteristics of the study population. There were 13,936,071 deliveries between 2006 and 2009 that met study criteria. The majority of deliveries were by physicians in the hospital (91.2%) followed by hospital midwives (7.78%), home midwives (0.44%), midwives in freestanding birthing centers (0.28%), and home deliveries by others (0.2%).
| Total | Hospital physician | Hospital MW | Freestanding BC MW | Home all MW | Home other |
|---|---|---|---|---|---|
| Total | 12,709,881 | 1,096,555 | 39,523 | 61,993 | 28,119 |
| Parity total | 12,658,411 | 1,090,290 | 39,254 | 61,051 | 27,643 |
| Para 0 | 5,193,419 (41) | 432,018 (39.6) | 14,036 (35.8) | 13,884 (22.7) | 5024 (18.2) |
| Para ≥1 | 7,464,992 (59) | 658,272 (60.4) | 25,218 (64.2) | 47,167 (77.3) | 22,619 (81.8) |
| GA total, wks | 12,709,881 | 1,096,555 | 39,523 | 61,993 | 28,119 |
| ≥41 | 2,006,179 (15.8) | 223,329 (20.4) | 10,419 (26.4) | 17,572 (28.3) | 7693 (27.4) |
| ≥42 | 810,809 (6.4) | 84,512 (7.7) | 3425 (8.7) | 5913 (9.5) | 3023 (10.8) |
| BW total | 12,709,881 | 1,096,555 | 39,523 | 61,993 | 28,119 |
| ≥4000 g | 1,120,028 (8.8) | 97,893 (8.9) | 6626 (16.8) | 13,653 (22) | 5387 (19.2) |
| ≥4500 g | 151,128 (1.2) | 11,093 (1.0) | 1171 (3) | 2821 (4.6) | 1256 (4.5) |
| Maternal age total, y | 12,709,881 | 1,096,555 | 39,523 | 61,993 | 28,119 |
| <25 | 4,392,994 (34.6) | 449,782 (41) | 9296 (23.5) | 10,102 (16.3) | 6097 (21.7) |
| 25-29 | 3,610,725 (28.4) | 317,099 (28.9) | 13,385 (33.9) | 19,292 (31.1) | 8315 (29.6) |
| 30-34 | 2,920,352 (23) | 218,075 (19.9) | 10,864 (27.5) | 18,916 (30.5) | 7602 (27) |
| ≥35 | 1,785,860 (14.1) | 111,599 (10.2) | 5978 (15.1) | 13,683 (22.1) | 6105 (21.7) |
| R/E total | 12,622,924 | 1,089,006 | 39,298 | 61,097 | 27,666 |
| NH white | 6,939,531 (55) | 572,702 (52.6) | 31,552 (80.3) | 55,466 (90.8) | 22,269 (80.5) |
| NH black | 1,710,594 (13.6) | 143,371 (13.2) | 1835 (4.7) | 1132 (1.9) | 2316 (8.4) |
| NH other | 846,850 (6.7) | 75,083 (6.9) | 1042 (2.7) | 1263 (2.1) | 809 (2.9) |
| Hispanic | 3,125,949 (24.8) | 297,850 (27.4) | 4869 (12.4) | 3236 (5.3) | 2272 (8.2) |
When compared with hospital births, home births were more likely to have a postdate pregnancy of 41 or more weeks: 28.3% for home births midwives vs 20.4% for hospital midwives and 15.7% for hospital physicians ( P < .001); and 42 or more weeks: 9.5% in home births midwives vs 7.7% for hospital midwives and 6.4% for hospital physicians ( P < .001). Women delivered at home by midwives were more likely to be 35 years old or older and more likely to have macrosomic infants. Women delivered by midwives at home were more likely to be non-Hispanic white when compared with hospital births.
Table 2 shows the total neonatal mortality (prior to 28 days) and relative risks by parity and weeks before and after 41 weeks gestation by the 5 groups of settings and attendants.
| Neonatal mortality | Per 1000 (n/total) | RR (95% CI) | P value |
|---|---|---|---|
| Hospital midwife | 0.32 (356/1,096,555) | 1 | |
| Hospital physician | 0.55 (6977/12,709,881) | 1.69 (1.52–1.88) | |
| Freestanding BC midwife | 0.59 (23/39,523) | 1.81 (1.19–2.75) | |
| Home midwife | 1.26 (78/61,993) | 3.87 (3.03–4.95) | |
| Home other | 1.87 (52/28,119) | 5.75 (4.31–7.68) | |
| Total | 0.54 (7486/13,936,071) | ||
| Neonatal mortality (para = 0) | |||
| Hospital midwife | 0.33 (141/432,018) | 1 | |
| Hospital physician | 0.57 (2946/5,193,19) | 1.74 (1.47–2.06) | |
| Freestanding BC midwife | 1.01 (14/14,036) | 3.1 (1.8–5.36) | |
| Home midwife | 2.19 (30/13,884) | 6.74 (4.55–9.96) | |
| Home other | 3.01 (15/5024) | 9.26 (5.45–15.72) | |
| Total | 0.56 (3146/5,658,381) | ||
| Neonatal mortality (para >0) | |||
| Hospital midwife | 0.32 (213/658,272) | 1 | |
| Hospital physician | 0.53 (3981/7,464,992) | 1.65 (1.43–1.89) | |
| Freestanding BC midwife | 0.36 (9/25,218) | 1.10 (0.57–2.15) | NS |
| Home midwife | 0.96 (45/47,167) | 2.97 (2.16–4.09) | |
| Home other | 1.43 (32/22,619) | 4.41 (3.05–6.38) | |
| Total | 0.52 (4280/8,218,268) | ||
| Neonatal mortality (<41 wks) | |||
| Hospital midwife | 0.34 (295/873,226) | 1 | |
| Hospital physician | 0.55 (5862/10,703,702) | 1.62 (1.44–1.82) | |
| Freestanding BC midwife | 0.48 (14/29,104) | 1.44 (0.85–2.46) | NS |
| Home midwife | 1.02 (45/44,421) | 3.03 (2.22–4.14) | |
| Home other | 2.12 (43/20,426) | 6.29 (4.57–8.64) | |
| Total | 0.54 (6259/11,670,879) | ||
| Neonatal mortality (≥41 wks) | |||
| Hospital midwife | 0.27 (61/223,329) | 1 | |
| Hospital physician | 0.56 (1116/2,006,179) | 2.04 (1.58–2.64) | |
| Freestanding BC midwife | 0.86 (9/10,419) | 3.17 (1.58–6.38) | |
| Home midwife | 1.84 (32/17,572) | 6.76 (4.42–10.36) | |
| Home other | 1.19 (9/7693) | 4.35 (2.17–8.72) | |
| Total | 0.54 (1227/2,265,192) |
Midwife home births had a significantly higher nearly 4-fold total neonatal mortality risk when compared with those delivered by hospital midwives (1.26 per 1000 births; RR, 3.87 vs 0.32 per 1000; P < .001).
Midwife home births of women with a first birth had a significantly higher nearly 7-fold risk of total neonatal mortality than those by hospital midwives (2.19 per 1000; RR, 6.74 vs 0.33 per 1000; P < .001) and a neonatal mortality more than twice that of those with a subsequent birth (2.19 vs 0.96 per 1000; P < .001).
Midwife home births of 41 or more weeks had a significantly higher nearly 7-fold risk of total neonatal mortality than those delivered by hospital midwives (1.84 per 1000; RR, 6.76 vs 0.27 per 1000; P < .001).
Table 3 shows the term early neonatal mortality (0-6 days) and relative risks by parity and weeks before and after 41 weeks gestation by the 5 groups of settings and attendants. Midwife home births had a significantly higher nearly 7-fold early neonatal mortality risk when compared with those delivered by hospital midwives (0.93 per 1000 births; RR, 6.6 vs 0.14 per 1000; P < .001).
| Early neonatal mortality | Per 1000 (n/total) | RR (95% CI) |
|---|---|---|
| Hospital midwife | 0.14 (155/1,096,555) | 1 |
| Hospital physician | 0.29 (3648/12,709,881) | 2.04 (1.73–2.39) |
| Freestanding BC midwife | 0.46 (18/39,523) | 3.26 (2.01–5.31) |
| Home midwife | 0.93 (58/61,993) | 6.6 (4.88–8.93) |
| Home other | 1.65 (46/28,119) | 11.73 (8.45–16.28) |
| Total | 0.28 (3925/13,936,071) | |
| Early neonatal mortality (P = 0) | ||
| Hospital midwife | 0.13 (58/432,018) | 1 |
| Hospital physician | 0.31 (1634/5,193,419) | 2.35 (1.81–3.05) |
| Freestanding BC midwife | 0.8 (11/14,036) | 5.94 (3.13–11.27) |
| Home midwife | 1.82 (25/13,884) | 13.62 (8.54–21.72) |
| Home other | 2.61 (13/5024) | 19.5 (10.71–35.48) |
| Total | 0.31 (1741/5,658,381) | |
| Early neonatal mortality (P >0) | ||
| Hospital midwife | 0.14 (95/658,272) | 1 |
| Hospital physician | 0.27 (1980/7,464,992) | 1.84 (1.5–2.27) |
| Freestanding BC midwife | 0.28 (7/25,218) | 1.93 (0.9–4.16) |
| Home midwife | 0.66 (31/47,167) | 4.62 (3.09–6.91) |
| Home other | 1.25 (28/22,619) | 8.71 (5.73–13.25) |
| Total | 0.26 (2141/8,218,268) | |
| Early neonatal mortality (<41 wks) | ||
| Hospital midwife | 0.15 (127/873,226) | 1 |
| Hospital physician | 0.29 (3066/10,703,702) | 1.97 (1.65–2.35) |
| Freestanding BC midwife | 0.35 (10/29,104) | 2.4 (1.27–4.55) |
| Home midwife | 0.8 (35/44,421) | 5.48 (3.78–7.96) |
| Home other | 1.88 (38/20,426) | 12.9 (9–18.51) |
| Total | 0.28 (3276/11,670,879) | |
| Early neonatal mortality (≥41 wks) | ||
| Hospital midwife | 0.12 (27/223,329) | 1 |
| Hospital physician | 0.29 (583/2,006,179) | 2.36 (1.61–3.47) |
| Freestanding BC midwife | 0.77 (8/10,419) | 6.25 (2.85–13.74) |
| Home midwife | 1.26 (22/17,572) | 10.28 (5.88–17.98) |
| Home other | 1.06 (8/7693) | 8.59 (3.93–18.79) |
| Total | 0.29 (648/2,265192) |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
