11w3d: Exhausted

In exactly four days time I will be making my way to the hospital for my NT scan. I am scared of all the things that can go wrong, and excited about what a milestone it will be if everything looks good.

So in order to get me into the spirit of the occasion, I have been doing what any good scientist would do, and reading through the literature surrounding the tests that will be conducted at this appointment, mainly, the NT scan and the blood tests.

The nuchal translucency (NT) test measures the thickness of the sack of fluid behind the neck of the fetus. In general, a fetus with a trisomy (three copies of a chromosome, rather than two) has a thicker NT than a chromosomally normal fetus.

The first figure below illustrates this observation. Each black dot represents two measurements (the crown-rump length and the NT thickness) of a single fetus that was subsequently found to have trisomy 21 (Down's Syndrome). The dark grey rainbow is the distribution of 90% of chromosomally normal fetuses. As you can see, in normal fetuses the NT thickness gradually gets thicker as the fetus gets larger. However, in trisomy 21 fetuses, the thickness remains relatively constant during this gestational period, with a mean thickness of 3.4 mm.

(from Kagan, et al., Ultrasound Obstet Gynecol 2008; 31: 618-624)

The second test is a blood test of the mother to measure our old friend beta-human chorionic gonadotropin (beta-hCG) as well as pregnancy-associated plasma protein-A (PAPP-A). The values on the axis are multiples of the median (MoM), that is, by how many-fold does a result differ from the median value from all normal women. By definition, the median beta-hCG for unaffected pregnancies is 1.0, and the median PAPP-A for unaffected pregnancies is also 1.0.

This second figure below shows how the blood tests from women with trisomy 21 fetuses varies from women with chromasomally normal fetuses. Each dot represents the values from a single patient with a trisomy 21 fetus. The unfilled oval represents the lab values of 90% of women with chromasomally normal fetuses. The median beta-hCG values were 2-fold higher and the the PAPP-A values were 2-fold lower in women with trisomy 21 fetuses.

(from Kagan, et. al., 2008, Ultrasound Obstet Gynecol, 31: 618-624)

So here's hoping that all my dots fall in the normal range, and I can pass this test and start to look forward to moving into the second trimester. It is still feeling unreal, so I hope that seeing a wiggling little fetus on the ultrasound next Tuesday will put some of my anxiety to rest.

References:

Kagan, K.O., Wright, D., Baker, A., Sahota., D., & Nicolaides, K.H. 2008. Screening for trisomy 21 by maternal age, fetal nuchal translucency thickness, free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A. Ultrasound Obstet Gynecol., 31: 618-624

10w2d Anxious

It is a long slow wait until my next ultrasound in mid-January. I have ordered a doppler, but it seems to be making its way to my home on foot, and is not due here for another week. Although the queasiness, fatigue, back-pain, and swollen breasts continue, it is not the concrete proof that I would like that everything is progressing well with this pregnancy.

My husband, on the other side, seems to have accepted the fact that our family will welcome another member in August next year. He is busy reading "First Time Parent" and making a long list of all the tasks that must be completed before then. He wants to start painting the nursery and buying furniture. The other day he started asking me questions like if we should alternate bottle with breast at night to allow me to get more sleep, and if we should use a crib in the nursery rather than a co-sleeper in our bedroom.

I responded to his thoughtful questions by bursting into tears. For me, it is all I can do to get through the next two weeks until the Week 12 scan. For him, he figures I've got the pregnancy handled, and his job starts in August. I am thinking fetus, and he is thinking newborn. I am so thankful that he realises that he is an equal partner in the upbringing of our child, but sometimes his go-go attitude is a little intimidating, especially when I can barely muster the energy to get off the couch.

7w6d Tomorrow

I have seen a lot of scans of my uterus over the past few years. I even have a few photos from my laparoscopy. Yet I have no idea what I will see tomorrow.

One one hand, the queasiness, fatigue, sore breasts and lower back pain suggests that I might be gestating something. On the other hand, these symptoms are all psychosomatic, and I know of plenty of women who have received terrible news at their first ultrasound scan.

Seeing a heartbeat tomorrow is both imaginable and completely impossible.

Tomorrow, we open Schrodinger's box, and hope he didn't share it with Pandora.