Sunday, March 16, 2014

MANA Study Part 3: Total Mortality Rates

You are reading Part 3 of my MANA study series. Click to view:

MANA Study Part 1: Intrapartum Mortality Rates

MANA Study Part 2: Neonatal Mortality Rates

MANA Study Part 3: Total Mortality Rates (currently reading)

MANA Study Part 4: Vaginal Birth After Cesarean

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Now it's time to put together what we know and figure out the total mortality rates. This is intrapartum mortality plus neonatal mortality. It's important to look at the total mortality as it really gives more complete picture.

As I have done with the previous two posts, I'm going to compare numbers a few different ways. I'll use the same information I did for intrapartum and neonatal comparisons plus I am adding in one more study, the CPM 2000 study, for total mortality comparisons. I'll explain why when I get there. So here they are again:

1. The MANA study - planned home births with a midwife in the USA, attended mostly by CPMs, LMs and LDMs (Certified Professional Midwives, Licensed Midwives and Licensed Direct-Entry Midwives)

2. The Birth Center study - planned births in select CABC-accredited birth centers with a midwife in the USA, attended mostly by CNMs (Certified Nurse Midwives)

3. The CPM 2000 study - planned home births with a CPM (Certified Professional Midwife)

4. USA hospitals - births in hospitals in the USA


ALL RATES DISCUSSED BELOW EXCLUDE ALL LETHAL ANOMALIES. The exception is the hospital group. Excluded from the hospital group are congenital malformations, deformations and chromosomal abnormalities from the hospital group. This may not include all lethal anomalies, as some may be labeled as something else, like cardiac disease, for example.


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First, let's compare the MANA study to the Birth Center study.

Total Mortality Rates, all risk:

MANA study = 2.06/1000

Birth Center study = 0.87/1000

For every 10,000 babies born at home, 20-21 babies will die. 

For every 10,000 babies born at a CABC accredited birth center, 8-9 babies will die.

As I mentioned previously, a part of this increase is due to the fact that the MANA study has more high risk pregnancies than in the Birth Center study. Let's compare low risk only.

Total Mortality Rates, low risk:

MANA study = 1.62/1000

Birth Center study = 0.87/1000

Why is a home birth two times more likely to end in death of a baby? The birth center studies is freestanding birth centers. These are two studies that look at out-of-hospital birth in the USA... why is there such a big difference?

For every 10,000 babies born at home to low risk mothers, 16-17 babies will die.

For every 10,000 babies born at a CABC accredited birth center, 8-9 babies will die.

What does this comparison show us?
1. It shows the increase risk to babies born out of a hospital to high risk mothers (2.06/1000 compared to .87/1000.... insane)
2. It shows the increase risk to babies born out of a hospital under the care of a non-nurse midwife (1.62/1000 compared to .87/1000... not acceptable)

(as I explained above, majority of the midwives in the MANA study are non-nurse midwives; majority of the midwives in the Birth Center study are nurse midwives)

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Now I will compare the MANA study to the CPM 2000 study. Why am I doing this? Because one of the defenses I have seen many, many times now is that home birth advocates are trying to blame the unlicensed midwives that took part in the MANA study for most or all of the bad outcomes. There are 971 births that were under the care of unlicensed midwives in the MANA study. So I am comparing the MANA study to the CPM 2000 study to see if that may potentially be the issue. Here are the outcomes:

Total Mortality Rates, all risk:

MANA study = 2.06/1000

CPM 2000 study = 2.0/1000



Total Mortality Rates, low risk:

MANA study = 1.62/1000

CPM 2000 study = 1.7/1000

As you can see, the mortality rates are nearly identical. 100% of the outcomes in the CPM 2000 study are Certified Professional Midwives. Are unlicensed midwives solely to blame for the bad outcomes in the MANA study? Or can we compare both the MANA study and the CPM 2000 study to the outcomes of the Birth Center study and conclude out-of-hospital births with non-nurse midwives substantially increase the risk of death for a baby? That's how it looks to me but you are free to interpret it however you'd like.

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Finally, I will compare the MANA study outcomes to hospital outcomes. Since I used two different cohorts for hospital births, I will compare both.

Please note: The hospital CNM group is mostly low risk women; the hospital MD group is low risk and high risk. MD refers not only to OB/GYNs but high risk pregnancy specialists, such as perinatologists and even other medical doctors who may deliver babies, even on rare occasions (such as ER doctors).

This first comparison has the hospital cohort that is a closer match to the MANA study cohort. I defined it in my post regarding neonatal mortality rates.

Total Mortality Rates:

MANA study = 2.06/1000

MANA study, low risk only = 1.62/1000

Hospital CNMs = 0.35/1000 to 0.55/1000

Hospital MDs = 0.43/1000 to 0.63/1000

Even compared to the hospital MD group - which has a higher percentage of high risk pregnancies than the MANA study - the risk is greater for babies born at home. Comparing low risk home birth to mostly low risk hospital birth and it is a risk of death 3-5x higher for babies born at home.


This next comparison has the hospital cohort that is much, much broader which gives MANA the advantage, as the MANA study includes an all-around much lower risk group of women in this comparison.

Total Mortality Rates:

MANA study = 2.06/1000

MANA study, low risk only = 1.62/1000

Hospital CNMs = 0.38/1000 to 0.58/1000

Hospital MDs = 0.52/1000 to 0.72/1000

Comparing all risk home births to all risk hospital births, a baby is 1.5 to 4 times more likely to die at home. Comparing low risk home births to mostly low risk hospital births, a baby is 3 to 4 times more likely to die at home.

Again, these figures give MANA the advantage as it includes a higher risk group of women for the hospital outcomes:

For every 10,000 babies born at home, 20-21 babies will die. 

For every 10,000 babies born at home to low risk mothers, 16-17 babies will die.

For every 10,000 babies born to mostly low risk mothers in a hospital, 3-6 babies will die.

For every 10,000 babies born to women of all risk in a hospital, 5-8 babies will die. 

I am going to make one final comparison, using the most recent figures I just outlined (with the hospital cohort that gives MANA the advantage with the lower risk group of women). I am going to compare hospital CNM outcomes to MANA study outcomes for all risk. I am doing so for three reasons:

1. The hospital CNM numbers are not strictly limited to low risk outcomes, like the MANA study low risk outcomes are. There is no way to completely filter out all high risk pregnancy outcomes from hospital data. While it is unlikely that any breech births or twins births are included in the hospital CNM outcomes, it is possible. Regardless, hospital CNMs care for mostly low risk women, but they do not care for only low risk women.

2. This shows why it is necessary for women to take proper screening measures to ensure a mother is low risk for out of hospital births. If she is high risk she should either switch to a hospital CNM or MD where proper monitoring/care for her high risk pregnancy can continue as it should to ensure the safest outcome for mother and baby. If a mother's low risk status is assumed and not confirmed with the necessary/recommended screening measures, she may actually be high risk but may think she is low risk.

3. If your home birth midwife brushes off your high risk pregnancy and/or refers to it as a "variation of normal," you are taking a big risk and you need to be aware of the odds.

Total Mortality Rates:

MANA study, all risks = 2.06/1000

Hospital CNMs, all risks = 0.38/1000 to 0.58/1000

This means a baby is 3 to 6 times more likely to die at home. That is an additional 15-18 babies per 10,000 that die at home under the care of a midwife that would have lived had they been born in a hospital under the care of a CNM.



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Conclusion: 
There currently are over 30,000 home births every year in the USA. This means, for women who are truly (confirmed) low risk, each year at least 31-41 babies die at home births that would have lived had they been born in a hospital. For high risk women, each year at least 29-34 babies die at home births that would have lived had they been born in a hospital.

The safest place of birth for a baby is in a hospital. For babies born outside of the hospital, it is important that their mothers be low risk (throughout pregnancy and during labor/delivery) and that the attendant be a Certified Nurse Midwife who practices under the guidelines set forth by CABC-accredited birth centers.



References:

1. MANA study: http://onlinelibrary.wiley.com/doi/10.1111/jmwh.12172/full

2. Birth Center study: http://onlinelibrary.wiley.com/doi/10.1111/jmwh.12003/full

3. CPM 2000 study: http://www.bmj.com/content/330/7505/1416

4. USA hospital neonatal mortality rates: http://wonder.cdc.gov/

5. There are two sources I have used for hospital intrapartum mortality rates:

    a. 0.3/1000 is from The World Health Organization:
http://whqlibdoc.who.int/publications/2006/9241563206_eng.pdf
(see Table 7.1 on page 21)

    b. 0.1/1000 to 0.3/1000 is from Judith Rooks:
Here are screen shots of a public, online discussion between Judith Rooks, CNM, MPH and Wendy Gordon, CPM, MPH.



As you can see, Wendy Gordon - one of the authors of the MANA study - did not dispute the rates provided by Judith Rooks. Neither Judith Rooks nor Wendy Gordon commented again after that. Eventually the thread - posted on the public Facebook page of an outspoken home birth advocate (The Feminist Breeder) - was deleted by the page admin.

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MANA Study Part 1: Intrapartum Mortality Rates

MANA Study Part 2: Neonatal Mortality Rates

MANA Study Part 3: Total Mortality Rates

MANA Study Part 4: Vaginal Birth After Cesarean


1 comment:

  1. Hi Dani,
    I found your blog via a comment/post on The Skeptical OB (of which I don't believe you are a mouthpiece or minion, by the way). I want to sincerely thank you for taking the extraordinary time and effort to create this easy to navigate overview of the MANA study. I had read, numerous times, from Dr Amy about the increased risk level of home birth, but I hadn't yet found on her site the actual breakdown or comparisons. So thank you very much for that!
    I live in Ontario, Canada and I do know (personally or by association) many women who chose, and continue to choose, home birth even for their first pregnancies, and thus far I don't believe any of these specific women had infant death or complications (the death I'm 99% certain, but with complications it is as you've mentioned....not everyone wants to share the lesser details of a home birth less it spoil the 'magical' image).
    My husband and I are on our 3rd pregnancy now, the first 2 were unsuccessful. Never at any point did either of us even remotely consider home birth, but even if we had it would be out of the question as we are now deemed 'very high risk'.
    I sincerely thank you for providing something I can steer people to when they argue 1) I don't know what I'm talking about 2) insist home birth is 'magical' and the only safe option and 3) believe that the US data (the only ones that seem to show up in the media) are really that accurate.

    Thanks so much, keep up the amazing work :)

    ReplyDelete