Pregnancy, Air Travel, and Radiation Exposure.

There has been some concern and some misconceptions regarding air travel risk during pregnancy. In general casual air travel is considered not to be an issue in terms of radiation exposure. However, those who travel frequently such as pilots, flight attendants, couriers, and very frequent business travelers are advised to reduce their flight time.

This paper from the American College of Obstetricians and Gynecologists reviews the guidelines in detail. Here's a summary:

~The magnitude of in-flight exposure depends on altitude and on the 11 year solar sunspot cycle. There is less exposure on a short-haul low altitude flight (SF - Seattle) vs a long-haul high altitude flight. Travel bet New York (NY) and Tokyo on transpolar flights approximates at 150 microsievert = 15 mrem whereas between NY and Seattle is 60 microsieverts = 6 mrem.

~Most radiation experts agree that there's no fetal harm such as mental retardation, growth restrictions, or miscarriages at a dose below 20 millisieverts (mSv) = 2 rem. The long term risk, however, in terms of future risks such as leukemias has not been established - neither confirmed nor ruled out.

~Maximum exposure for a woman through her 40 week pregnancy is advised to be 1 mSv = 100 mrem. So the 2 trips described above would give 15% and 6% of the maximum permitted exposure. You would need at least 7 trips of the transcontinental or 17 trips of the intercontinental duration to reach the maximum dose allowed. The actual amount during each flight can be calculated here if you know the altitudes.

~ The FAA gets an advisory about the solar activity and when to avoid routes when the activity is peaking. Real time proton intensity info is available online from Space Environment Center of the National Oceanic and Atmospheric Administration.

In terms of non-radiation risks with air travel, it should be noted that the safest time to travel is considered to be during the second trimester between 18-24 weeks when the risks for miscarriages and preterm delivery are lowest. In an uncomplicated pregnancy, it is advised not to travel after 36 weeks. In a complicated pregnancy the recommendations would be different.

And as always it is best to consult with your doctor if you have any concerns regarding traveling while pregnant.

Canker Sores

Canker sores or aphthous ulcers are small, painful, shallow ulcerations that occur on the soft tissues inside the mouth. Stress or tissue injury is believed to contribute to the development of canker sores, although the actual cause is unknown. Other possible factors include immune system dysfunction, vitamin deficiencies such as B-12, zinc, folic acid or iron, disease of the gastrointestinal tract, food allergies, or hormonal changes such as menstrual periods. There can also be a hereditary predisposition to developing these sores. They are not contagious and normally resolve without any intervention in 10-14 days.

Occasionally these sores can be recurrent or large and complex. For these cases there are several treatment options. Dr. Nasim Fazel makes the following recommendations.

• Topical therapy - Steroid compounds such as flucinonide (Lidex) or clobetasol gel for lesions which are easily within reach or dexamethasone (Decadron) elixir (0.5 mg/5ml) to swish around in the mouth for lesions that are in the back of the throat.
• Systemic therapy - Several immune system modifying medications may be used for the more severe cases. These include prednisone either in a short term therapy of 40-80 mg every day for 4-5 days or a long term dosing regimen with gradual taper; pentoxifylline (Trental) 400 mg three times a day for at least 3-6 months and usually for 1 year; colchicine 0.6 mg 2 to 3 times a day, dapsone 100-200 mg daily or azathioprine (Imuran) 50 mg twice daily for 2 weeks. Each of these medications has its own set of side effects which should be weighed against the benefits.
• Pain control therapy - Zilactin which is an over the counter gel, sucralfate(Carafate) to provide a protective coating over the ulcer, or viscous lidocaine 2% to be taken about 20 minutes before meals to reduce the discomfort while eating.

What ever option you chose, please don't do this.

Photo: courtesy of kidshealth.

Breast Feeding And Smarter Babies

A new study concludes that breast feeding may help increase IQ in the setting of the right genes. The study followed 3000 children who were fed by breast milk and by bottled formula. Nine out of ten children scored higher by 7 points on the IQ scale if they were breast fed. Breast milk contains fatty acids that help the growth of brain cells. Ninety percent of babies carry the gene variant (C version of FADS2 ) which helps the process by which these fats stimulate brain development. The children who carried this gene and who were breast fed were the ones who scored higher on the IQ test.

One group of the children was born in New Zealand between 1972-73. These children were tested at ages 7, 9, 11, and 13. Fifty seven percent of these children were breast fed. The other group of children was born in England between 1994-1995, and 48% of these children were breast fed. They were tested at age 5. Both groups were tested with Wechsler.

The results were the same for babies with normal or low birth weight. There was not a difference noted in those who were born into a high or low-social-class, or in those who had mothers with high or low-IQs. Children with the FADS2 ‘C’ genotype were no more likely to have been breastfed than children with the FADS2 ‘G’ genotype.

This data helps support the interactive roles that both genetic and environmental factors play in our development.

References: please see links.

Photo: courtesy of msnbc.

When Is the Best Time To Get Pregnant?

I am often asked about how to predict the best time to attempt pregnancy each month. In general the most fertile time for a woman is 14 days before her next menstrual cycle. If the cycle lasts 28 days, counting the first day of bleeding as day 1, then day 14 is when she should be ovulating. If the cycle is 30 days then it would be 30 minus 14 which would be day 16 of the cycle. This ovulation calculator may be helpful.

For a more accurate prediction there are several kits available over the counter which help eliminate some of the guess work. These may be especially helpful for women who have irregular cycles and who cannot reliably predict their peak ovulation time just by counting days. A few kits that are recommended are Clearblue, Ovuquik, and First Response. Clearblue ranges from $20 to $30 for 7 - 10 test sticks in each box.

These kits work by detecting an increase in the level of luteinizing hormone (LH) in the urine. The hormone is produced by the pituitary gland in the brain. Normally luteinizing hormone level peaks 24-36 hours before ovulation - the release of the egg from the ovary. It is then excreted via the urinary system where it is detected by the monitor stick which is included in the kits.

It is recommended to start testing 3-4 days before the expected day of ovulation. The best time of day to check is in late afternoon - 2 pm and later or at least no earlier than the second morning urine. It is best to avoid the first morning urine because LH can accumulate overnight and show a higher level in that sample. Once the meter reads as positive then the LH surge has occurred. The best time for intercourse then would be on the same day or 12-24 hours later.

If you are not using the kit, then it is recommended to have intercourse every other day starting 4-5 days before the expected time of ovulation. Other tips to help facilitate pregnancy is to avoid using any sperm toxic lubricants. Vegetable oil or Pre-Seed vaginal moisturizer is OK to use. After intercourse lay on your back with knees up for 20 minutes. And if you don't achieve the desired outcome then just try again.

Disclosures: I have no financial interest in any of the companies mentioned.

Which Days Are Good To Test With Fertility Kits

Here's a quick guide as to when to start testing with the kit. If the cycles are variable then use the shortest cycle period in the last 6 months.

If Cycle Length then Start Testing Day
If 21 days, then start testing at day 5
22 ---5
23 ---6
24 ---7
25 ---8
26 ---9
27 ---10
28 ---11
29 ---12
30 ---13
31 ---14
32 ---15
33 ---16
34 ---17
35 ---18
36 ---19
37 ---20
38 ---21
39 ---22
40 ---23
41 ---24
42 ---25

How Long Does It Take to Get Pregnant?

Pregnancy rates with "normal" fertility should be expected to be:
-1 month 25%
-6 months 60%
-9 months 75%
-12 months 85%
-18 months 90%

Infertility occurs in 15% of reproductive age couples. It is defined as no pregnancy in 12 months of unprotected intercourse. However, infertility evaluation may be started sooner depending on the woman's age.

In general if there is no history or risk factors for infertility the recommendations for starting infertility evaluation are:
- women under 35 years old to start at 12 months
- women 35-39 to start at 6 months
- women over 40 to start at 3 months

Image courtesy of midcoast abstract gallery.

Lybrel - A Continuous Oral Contraceptive

The FDA recently approved Lybrel, a new oral contraceptive, which is taken continuously through the year without a pill-free interval. The pills contain levonorgestrel (.09 mg) and ethinyl estradiol (20 mcg).

This type of regimen may be useful in women in whom oral contraceptives are used to treat painful menses (dysmenorrhea), endometriosis, acne, and polycystic ovary syndrome. It may also be more effective than cyclic contraceptives in improving menstrual related headaches and mood changes.

Continuous oral contraceptive use should eventually eliminate menstruation. However, unexpected bleeding is the most common side effect. The incidence of breakthrough bleeding decreases with time. In clinical studies, about half of the women had bleeding at pack 3, and 20% at pack 13.

It should be noted that the long-term effects of continuous regimens have not been evaluated.

References: please see links.

Photo: courtesy of Slate.