DDRC Healthcare – looking at things slightly differently…. Women & Diving Compiled by the DDRC...
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Transcript of DDRC Healthcare – looking at things slightly differently…. Women & Diving Compiled by the DDRC...
DDRC Healthcare – looking at things slightly differently…. Women & Diving
Compiled by the DDRC Healthcare research department
www.ddrc.org
facebook and twitter - @DDRCPlymouth
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%
10%
15%
20%
25%
30%
35%
40%
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%
30%
35%
40%
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%
35%
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
Not for profit charitable organisation Founded over 30 years agoEmergency recompressionFitness to dive advice MedicalsEducationResearchHyperbaric oxygen therapies
Who and What is DDRC Healthcare?