QuestionQUESTION: Hello, I am a Labor and Delivery nurse in Denver CO. I am 24 years old and
had a baby girl 15 months ago. We have been trying again to conceive, my
last period was 9/21/2007 however, I ovulated on October 9-11 according to
my monitor. I took three pregnancy tests at home and all three came back
with a very faint positive line. My cycle is typically about 30-31 days. My
question is why do I feel like I am going to start my period but I have not? All
I have had is VERY light brown spotting and a feeling of heaviness in my
abdomen like when I am about to menstruate. Should I have my blood drawn?
Why is the line so faint? Thanks so much! I typically only deal with women
that are past their first trimester.
ANSWER: Dear Jessica,
If you ovulated approximately 10/10 (splitting the difference), implantation would not have occurred until anytime between 10/16-10/22. hCG is made by the cells that form the placenta, which nourishes the egg after it has been fertilized and becomes attached to the uterine wall. Levels can first be detected by a blood test about 11 days after conception and about 12-14 days after conception by a urine test. In general, the hCG levels will double every 48-72 hours. So, most likely your levels are just not quite high enough yet to get a strong positive reading with the HPT since you are only about 14 days post-ovulation/conception today.
As long as the pregnancy continues along appropriately (good implantation and no other abnormalities at all) your levels will continue to rise. I would suggest simply waiting another week and re-testing. By then I'd bet you'll have a strong positive (given you have no period, of course). After that, you can go ahead and schedule your first prenatal visit. Remember to note to your OB doctor that you were using an OPK and that ovulation was indicated 10/9-11. Otherwise, they may think you are about a week further along than you actually are based on LMP. Your initial ultrasound should confirm dating, but this will help in any discrepancy from the get-go. You should be at 4 weeks today if conception occurred on 10/10. At 6 weeks you can usually visualize heart activity via ultrasound.
The feeling of being about to menstruate is something that is yet to be seen. If the pregnancy progresses normally, it is likely just due to the hormone fluctuations happening right now. If there is an issue with the pregnancy or if conception has not actually occurred and you are just late, you will begin a period and the symptoms are related to that.
I hope this information has helped you and answered your questions. I wish you well.
Brenda
---------- FOLLOW-UP ----------
QUESTION: Hi Brenda,
First off, thank you for your email advice. Since I last wrote, I have had two
more positive hpt's. I went to doctor today. They said my urine preg. test was
negative (then the lab tech told me it was a faint positive?) but then I told
them I still have not had my period. They then told me come back in two
weeks. They took blood after I told them about the hpt's. When I got home I
did another urine test and it was faint positive but darker than when I first
had written you. I will have my results tomorrow. Can the blood test results
come back fasely negative if it is too early?
AnswerDear Jessica,
It depends upon what type of blood test they run. The qualitative blood pregnancy test will return a positive/negative result and is only slightly more accurate/reliable than a urine test. A quantitative blood pregnancy test (serum beta hCG) is much more definitive. This test measures the actual amount of hCG present in the bloodstream. Any amount of 25 mIU/ml or more would be considered positive for pregnancy. (Non-pregnant levels are 0-5 mIU/ml.)
A qualitative urine or blood hCG test is typically considered accurate as early as 10 days after a missed menstrual period if a woman wishes to confirm whether or not she is pregnant. A quantitative test can detect hCG even earlier - often as early as 10 days after conception, which is usually right before a missed period. So actually the serum beta hCG will be more accurate early on than the urine test or the qualitative blood test.
I hope that helps you. Be well.
Brenda
