A comparison of infant death rate by model of care

Week three of classes brought a lab of choice assignment. After much debate I choose to compare the neonatal outcomes of CNM-based care against MD-based care.  I compiled the statistics from over 12.5 million singleton (1 baby), vertex (head down),vaginal births from 35-42 weeks of gestational age over the six year span of 1999-2005. 

Question:

What is the safest model of care for a prospective low-risk mother and her child?

Background:

There are two main models of care regarding the pre-natal and birth period: the nurse midwife-led model of care and the medical doctor–led model of care. Throughout most of the world midwifes are the primary caregivers for low-risk mothers. In the United States M.D.-based care has become the standard.

Hypothesis:

The midwife-led model of care provides maternal and neonatal outcomes that are equal to or exceed that of other models of care.

Procedure:

Data stating infant death rates in the United States was collected from the Centers for Disease Control and was then filtered by controlling for type of birth attendant, gestational age at live birth, and delivery method.

In total, the statistics from 12,589,251 singleton, vertex, vaginal births of newborns from 35 - 42 weeks gestation were compared, with the variable being the type of attendant that supervised the birth. Statistics concerning births overseen by doctors of osteopathy or direct entry midwives, births before 35 weeks, births after 42 weeks and births ending in cesarean deliveries were dismissed.

Data:

CNM Attended Births from 1999-2005

Medical Attendant	Delivery method	Gestational age in weeks	Births	Infant death rate per 1,000
Certified Nurse Midwife	Vaginal	35 weeks	25,237	5.36
Certified Nurse Midwife	Vaginal	36 weeks	49,951	4.35
Certified Nurse Midwife	Vaginal	37 weeks	105,442	2.96
Certified Nurse Midwife	Vaginal	38 weeks	224,156	2.18
Certified Nurse Midwife	Vaginal	39 weeks	151,988	1.79
Certified Nurse Midwife	Vaginal	40 weeks	360,871	1.66
Certified Nurse Midwife	Vaginal	41 weeks	192,273	1.72
Certified Nurse Midwife	Vaginal	42 weeks	61,663	2.59

CDC (2010)

MD Attended Births from 1999-2005

Medical Attendant	Delivery method	Gestational age in weeks	Births	Infant death rate per 1,000
Doctor of Medicine	Vaginal	35 weeks	292,614	6.7
Doctor of Medicine	Vaginal	36 weeks	530,446	4.88
Doctor of Medicine	Vaginal	37 weeks	1,062,320	3.43
Doctor of Medicine	Vaginal	38 weeks	2,144,586	2.49
Doctor of Medicine	Vaginal	39 weeks	3,145,543	2.0
Doctor of Medicine	Vaginal	40 weeks	2,754,870	1.82
Doctor of Medicine	Vaginal	41 weeks	1,292,051	1.95
Doctor of Medicine	Vaginal	42 weeks	419,396	2.59

CDC (2010)

Results:

Medical Attendant	# of births from 1999-2005	Average Infant death rate per 1,000
Certified Nurse Midwife	947,425	2.82
Doctor of Medicine	11,641,826	3.23

Infant death rates from births supervised by certified nurse midwifes are lower at every stage of gestational age except for at 42 weeks, where both CNMs and MDs have an infant death rate of 2.59. Overall, CNMs have a lower average infant death rate of 2.28 compared to the MDs rate of 3.23.

This data supports but does not prove the hypotheses that the midwife-led model of care provides maternal and neonatal outcomes that are equal to or exceed that of other models of care. In order to solidify results intervention rates, cesarean rates, infant Apgar scores as well as maternal mortality and morbidity would also have to be studied.

Conclusion:

When comparing the infant death rates of Certified Nurse Midwives and Doctors of Medicine in the United States from 1999-2005, adjusting for gestational age at live birth and delivery method it has been concluded that the results support the hypotheses that the midwife-led model of care provides maternal and neonatal outcomes that are equal to or exceed that of other models of care. For births that occurred during the gestational age weeks 35-41 CNMs had lower infant death rates when compared to the infant death rates of MDs. For births that occurred during the 42^nd week, both CNMs and MDs had infant death rates of 2.59.

References:

Declercq, E., Sakala, C., Corry, M., Applebaum, S. (2006, October). Listening Mothers II: Report of the second national U.S. survey of women’s childbearing experiences. Retrieved from: http://www.childbirthconnection.org

Hatem M, Sandall J, Devane D, Soltani H, Gates S. Midwife-led versus other models ofcare for childbearing women. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD004667. DOI: 10.1002/14651858.CD004667.pub2

United States Department of Health and Human Services (US DHHS), Center for Disease             Control and Prevention (CDC), National Center for Health Statistics (NCHS), Office of Analysis and Epidemiology (OAE), Division of Vital Statistics (DVS), Linked Birth / Infant Death Records 1999-2002 on CDC WONDER On-line Database. Accessed at http://wonder.cdc.gov/lbd-v2002.html

 on Feb 5 2011          4:32:18 PM

United States Department of Health and Human Services (US DHHS), Center for Disease             Control and Prevention (CDC), National Center for Health Statistics (NCHS),  Office of Analysis and Epidemiology (OAE), Division of Vital Statistics (DVS), Linked Birth / Infant Death Records 2003-2005 on CDC WONDER On-line Database. Accessed at http://wonder.cdc.gov/lbd-current.html

 on Feb 5 2011             4:33:02 PM