1+1=2+ɛ... +δ

I have a confession to make. I've been unduly withholding information from you. But I think time has come to fill you in and I hope the following will clarify some things about my recent absence and brevity. During the last months, I've been more of a bumblebee than a bee: Yes, I'm pregnant! Here's a short summary of what was written between the lines.

Late April, due to an overactive Icelandic volcano, Stefan and I had to take a 3000 km road trip from Sweden to Germany and back. Unlike other primates, humans belong to the category of "nonseasonal breeders." Nevertheless, for as long as there's birth statistics, 10-20% seasonal variations in human live births have been documented. Confusingly though, the seasonal peak has changed over decades and seems to depend on age and other demographic factors as well. So spare me the comments about spring feelings. For what humans are concerned, "spring feelings" is a cocktail.

Briefly before my trip to Perimeter Institute in May, I got a positive result on the pregnancy test. Pregnacy tests are sensitive to the human chorionic gonadotrophin (hCG) hormone that is detectable after implantation of the fertilized egg. Modern pregnancy tests are amazing accurate. You can now also have them with a digital display and they provide estimates for the weeks after conception. They work up to 4 days before the missed period. In a few years, pregnancy tests will probably have a speech output and automatically submit the result to your twitter feed.

I dubbed the little clump of rapidly dividing cells Epsilon.

My stay at Perimeter Institute in May was mildly speaking scientifically not very productive. I started getting very sick briefly after my arrival. It's a miracle I managed to sit through the workshop on the Laws of Nature - and to even write a blogpost about it. My flight back to Stockholm was a nightmare. I spent 14 hours holding onto a sick bag, pressing a lemon scented face towel to my nose, trying to escape the food smell. Folk wisdom says nausea during early pregnancy is worse with girls and twins.

A word on counting the pregnancy length. Historically, the length of the pregnancy is not counted from conception on (typically unknown), but from the first day of the last menstrual period. This is known as "gestational age" and used by all doctors, books, and most other references (with a few exceptions). The gestational age, which I'll also use in the following, is approximately two weeks longer than the actual age of the embryo, also known as "embryonic age."

At about 7 weeks, the heart starts beating.

Back in Stockholm, at about 8 weeks, I went to the first ultrasound exam. The doctor didn't speak English too well. "You know," he said, "you have twilights." - "I have what?" He turned the screen around and showed me the image (see left). "Twins!" I said. And so to Epsilon was added Delta. If you haven't seen an ultrasound image before, dark means little reflection (sonolucent). Here, the black ovals are basically liquid-filled: the amniotic sacs. In the lower one you see very nicely the umbilical cord. The embryos are about 18 mm (crown to rump).

A twin pregnancy has advantages and disadvantages. There's a long list of possible additional complications with multiple pregnancies, which is why it's automatically considered a "high risk pregnancy." The advantage is the mother gets additional screenings to prevent these complications.

Just in time for our summer workshop, the nausea finally started fading. Clothes started getting a little tight though, as an observant eye might have noticed on the conference photo.

The average length of a human pregnancy is 40 weeks (gestational) and it's roughly divided into 3 trimesters, each bringing its own challenges. The first trimester ends at week 12, the second at week 27. From 9 weeks on, the embryo is called a fetus. The risk of miscarriage during the first trimester is very high, estimates range from one in 8 to one in 5 pregnancies that end by spontaneous abortion in that early stage. In the first 12 weeks, all the major organs are formed and working, though it takes several more months for them to mature - the last organ to fully mature is the lung. If anything goes wrong in the critical first steps, the embryo is not viable. Some reasons for miscarriage are known and are treatable, but by and large the doctors don't know much and can do even less at these stages. This is my second pregnancy. The first one ended in a miscarriage at 11 weeks. Of course I knew the statistics. But I didn't realize what it means till it happened to me and I suddenly learned how many people I knew had made the same experience before.

At 14 weeks, I went to the second ultrasound. The doc found two placentas, which means it could be fraternal or idential twins, but more likely fraternal. In the ultrasound image to the left you see them lying on top of each other, both heads to the right. (I've blurred out some details in the header for privacy reasons.) Crown to rump length is about 8 cm.

After that, Epsilon and Delta got too large to fit on a single ultrasound image. Then, the docs start measuring the sizes of single organs instead. The next ultrasound, "the big one" as they call it, is at 20 weeks. With this ultrasound, the fetus' organs are screened to detect possible problems. The outcome is some sort of risk assessment. In our case, the doctors didn't find any reason for concern. Kidneys and bladders were working properly. They did an ultrasound of the hearts, and measured the blood flow. They showed us the main arteries, the brains, the stomachs, the legs and hands. I was less impressed by the technique itself than by the resolution and, most of all, by what the doctor managed to read out of the pictures. We had this "big ultrasound" done in Germany (it has to be done by some particular week in case a severe problem calls for a late abortion), so Stefan could come and watch.

The doctor told us Epsilon and Delta are two girls.

Since then, Epsilon and Delta, and so my belly, have been steadily growing. The little ones are well and kicking (both me and each other), while I'm having some trouble coping with the adjustment. My sudden hospitalization some weeks ago was very likely related to the pregnancy, though the actual problem remained mysterious. Worse, only a week later I had the questionable honor to spend another night in a hospital, this time for a completely different reason. Again the doctors insisted on many tests but eventually found nothing in particular. The pregnancy bible tells me helpfully that I should be feeling great during the 2nd trimester. Well, so much about statistics.

In any case, my employer is informed now, the wheels of bureaucracy are turning, and if everything works out alright I'll go on maternity leave mid of November. As you know, Stefan lives in Germany while I live in Sweden, so our situation is a little complicated. The health insurance issues are a big annoyance, and that's only part of the problem. Luckily though, both the Swedes and the Germans are very generous with parental leave, so we'll have some time to reorganize our lives. For now, Stefan is moving into a larger apartment while I'm enjoying the pleasantries of maternity wear.