DDRC Healthcare – looking at things slightly differently…. Women & Diving

Compiled by the DDRC Healthcare research department

www.ddrc.org

research@ddrc.org

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Women and Diving

The subjects no male instructor really wants to talk about!

The menstrual cycle

Pregnancy

Women and Diving

Gender susceptibility and DCI

The menstrual cycle and DCI

Pregnancy

Women and Diving – Gender & DCI

Gender - men and women - differences - and DCI risk?

Early altitude studies were inconclusive, controversial and not always in agreement

Recent diving and altitude studies tend to agree

Women do not appear to be more at risk of diving DCI than men for similar diving habits

Women and Diving the Menstrual

Cycle

Schematic of the hormonal trials and tribulations of the menstrual cycle!

Women and Diving – the Menstrual Cycle

The menstrual cycle

The menstrual cycle (M/C) and DCI

The oral contraceptive pill (OCP) and DCI

Women and Diving – the Menstrual Cycle

Between the 1970s and up to 1998 studies showed possible relationship between the M/C and DCI – both altitude and diving studies

Between 1998 and 2006 more structured studies from both altitude and diving environments began to show there may be a relationship between DCI and time in the M/C

Women and Diving – the Menstrual Cycle

How reliable were these later studies?

Only diagnosed and treated in a chamber

Exact time in MC of the DCI

OCP vs non-OCP

Diving and menstrual diary data

Military data

Women and Diving – the Menstrual Cycle

The Lee study 2003 normalised data

0%

5%

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15%

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45%

Week 1 Week 2 Week 3 Week 4

Week in the menstrual cycle

Non OCP OCP

DDRC data 28 day cycles only

0%

5%

10%

15%

20%

25%

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35%

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45%

Week 1 Week 2 Week 3 Week 4

Week in the menstrual cycle

% o

f R

PD

D

Non OCP OCP

DDRC study normalised data

0%

5%

10%

15%

20%

25%

30%

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40%

Week 1 Week 2 Week 3 Week 4

Week in the normalised menstrual cycle

Non OCP OCP

Reported incidents of DCI over the four weeks of the M/C

Results from different studies:

The non-OCP (purple bars) incidents of DCI show similar trends, with fewer DCI in the third

week

Women and Diving – the Menstrual Cycle

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Day of the menstrual cycle

Hor

mon

e co

ncen

trat

ion

Progesterone

Estradiol

FSH

LH

Women and Diving – the Menstrual Cycle

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Day of the menstrual cycle

Hor

mon

e co

ncen

trat

ion

Women and Diving – the Oral Contraceptive

A woman on the OCP has a pharmaceutically driven MC

The debate surrounding the OCP is inconclusive and research results are not always in agreement

Due to the variations in methodologies, types of OCP, missing information, and differences in analysis

Women and Diving – the Oral Contraceptive

Research by DDRC showed women use the OCP to avoid a bleed to suit their social and work lifestyles, therefore shortening (21 days) or lengthening (60 days) the cycle for their own convenience

The jury is still out, with the debate regarding the risk factor between OCP usage and DCI on-going

It will remain unclear until OCP usage is more accurately recorded in diving research studies

Women and Diving - Pregnancy

There are no studies to say it is safe to dive whilst pregnant

BUT there is also no conclusive evidence that diving will cause an increased risk to the foetus

Therefore it is not possible to recommend or establish safe limits to dive whilst pregnant

Women and Diving - Pregnancy

Studies on animals have been contradictory

Early research work on animals concentrated on foetal susceptibility to DCI

Foetal circulation differs from the adult

Women and Diving - Pregnancy

In the adult almost all the output from the heart travels through the lungs where small bubbles are removed

In the foetus the circulation bypasses the lungs so any bubble that forms could be potentially life threatening

Women and Diving - Pregnancy

Human retrospective studies (questionnaires) have suffered from small numbers and problems with methodology

A study by DDRC (2006) showed that even though 129 women reported 157 dived pregnancies from 1465 dives no conclusions could be reached regarding problems when diving whilst pregnant.

Women and Diving - Pregnancy

To detect a meaningful increase in birth defects from diving whilst pregnant……

4000 women would need to dive all the time during pregnancy

Clearly this is not ethical or feasible!

The way forward remains elusive

Women and Diving - Summary

Research shows:

Women do not seem to be at greater risk of DCI than men for the same profiles

Some women, not on the OCP, may be at a greater or lesser risk of DCI over the MC, depending on the time in the MC

The jury is still out regarding OCP and DCI risk

It is not possible to recommend or establish safe limits to dive whilst pregnant

Further reading

All the subjects outlined in this lecture are

covered in much greater depth in the book

Women and Pressure: Diving and Altitude

ISBN 978-1-930536-60-9

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