Menstrual Irregularities and Early Pregnancy Signs

Q: Menstrual Irregularities and Early Pregnancy Signs

Hello, based on the information you provided： <br>1. <br>On November 10, at the medical center, the ultrasound of the neck translucency and abdominal ultrasound showed a Crown-Rump Length (CRL) of 6.33 cm, corresponding to a Gestational Age (GA) of 12 weeks and 5 days. <br>Genera

Menstrual issues

Hello, Doctor: Here’s the situation...
My menstrual cycle dates are March 4, March 31, April 29, May 27, June 24, and July 22 of 1999.
I had an encounter with partner A on August 1, but there was no complete penetration; however, I felt some contact.
Then, on August 20, when my expected period was due, I experienced some light bleeding that lasted a shorter duration.
Later, on August 29, I had an encounter with partner B, and on September 25, I discovered that I was pregnant.
I went to a clinic for an ultrasound, which showed a gestational sac (GS) measuring 12.6 mm, corresponding to approximately 4 weeks and 3 days, with a variation of 1 week.
On September 30, another ultrasound showed a crown-rump length (CRL) of 3.8 mm, and I heard the heartbeat that day.
On October 6, the ultrasound indicated a CRL of 1.07 cm, corresponding to a gestational age (GA) of 7 weeks and 1 day.
During my official prenatal check-up at a medical center on November 10, the nuchal translucency ultrasound showed a CRL of 6.33 cm, corresponding to a GA of 12 weeks and 5 days.
I would like to ask:
1.
Is the child likely from that encounter? Could it possibly be from August 1? Although there was no complete penetration, there was some contact.
Is there a possibility that the male partner's excitement could have resulted in pre-ejaculate fluid that led to my pregnancy?
2.
Could the pregnancy be from the August 1 encounter, but the implantation occurred later or the embryo developed slowly, causing the bleeding on August 20 to be a false period? Because during the ultrasound on November 10, the doctor mentioned that the gestational age was one week ahead (considering the August 20 date as 11 weeks, but the ultrasound showed over 12 weeks).
I asked the doctor, and he kept saying that my cycle is irregular or that I might have misremembered the last menstrual date (which I recorded as August 20).
However, I have been keeping track of my menstrual dates, and since the bleeding on August 20 was lighter and shorter, I began to suspect it might have been a false period.

3.
During subsequent prenatal check-ups, the doctor mentioned that the size was approximately normal, but during the 32-week check-up, the doctor said the gestational age was one week ahead.
At the 34-week check-up with a detailed ultrasound, the report indicated a head circumference of 35+ and an abdominal circumference of 37+.
Is this normal? Does it relate to the time of conception? I apologize for the trouble and appreciate your help in answering my questions!

Niming, 20~29 year old female. Ask Date: 2011/04/23

Dr. Lü Lizheng reply Obstetrics and Gynecology

Hello, based on the information you provided:
1.
On November 10, at the medical center, the ultrasound of the neck translucency and abdominal ultrasound showed a Crown-Rump Length (CRL) of 6.33 cm, corresponding to a Gestational Age (GA) of 12 weeks and 5 days.
Generally, the gestational age is calculated by subtracting two weeks from the pregnancy weeks, which means that 12 weeks and 5 days minus two weeks equals 10 weeks and 5 days, or 75 days.
Counting back 75 days from November 10, the estimated conception date would be around August 27.
2.
On October 6, the abdominal ultrasound showed a CRL of 1.07 cm, corresponding to a GA of 7 weeks and 1 day.
Using the same calculation method, the gestational age of 7 weeks and 1 day minus two weeks equals 5 weeks and 1 day, or 36 days.
Counting back 36 days from October 6, the estimated conception date would be around August 31.
3.
According to the above calculations, the estimated conception dates are around August 27 or August 31, with a margin of error within 7 days.
The only possible conception date with Subject B is August 29.
Subject A had intercourse on August 1, which is more than 7 days away from the estimated conception date, making it unlikely.
4.
At the 32-week prenatal check-up, the size variation among fetuses is significant, and the measurements are no longer accurate.
Early pregnancy data should be used for more precise estimations.
5.
Modern technology has advanced significantly; after birth, a cotton swab can be used to collect oral cells from the baby, which can then be tested for chromosomes.
This can be compared with the male partner's chromosomes to confirm paternity.
There should also be plenty of similar information available online for reference.
Wishing you peace and health,
Dr.
Lu Li-Cheng,
Director of Obstetrics and Gynecology, Taoyuan Hospital, Department of Health.

Reply Date: 2011/04/23

More Info

Understanding menstrual irregularities and early pregnancy signs can be quite complex, especially when there are multiple factors at play, such as irregular cycles, potential conception dates, and the nuances of early pregnancy symptoms. Let's break down your questions systematically.

1. Conception Date: Based on the timeline you've provided, it is indeed possible for the conception to have occurred during the encounter on August 1, even if penetration was not complete. Sperm can be present in pre-ejaculate fluid, which may lead to pregnancy if it comes into contact with the vaginal canal. However, the timing of your ultrasound measurements suggests that the most likely conception date aligns more closely with the encounter on August 29, as the gestational age (GA) calculated from your ultrasounds indicates a conception around that time.
2. False Menstrual Period: The bleeding you experienced on August 20 could potentially be a form of implantation bleeding rather than a true menstrual period, especially if it was lighter and shorter than your typical cycle. Implantation bleeding can occur when a fertilized egg attaches to the uterine lining, which might explain the unusual characteristics of that bleeding. The discrepancy in gestational age noted by your doctor could also be attributed to variations in ovulation timing, especially given your irregular cycles. If your cycles are not consistent, it can lead to confusion regarding the exact date of your last menstrual period (LMP) and the timing of ovulation.

3. Growth Measurements and Gestational Age: It's common for ultrasound measurements to vary slightly from the expected gestational age based on LMP, especially in the second and third trimesters. The growth of the fetus is typically assessed through various parameters, including crown-rump length (CRL) in early pregnancy and head circumference (HC) and abdominal circumference (AC) later on. The measurements you provided indicate that your baby is growing well, and slight variations in size are normal. The fact that your doctor noted a difference in gestational age during your 32-week appointment could be due to the natural variability in fetal growth rates.
In summary, while it is possible for the encounter on August 1 to have resulted in pregnancy, the ultrasound data suggests that the more likely conception date is August 29. The bleeding on August 20 may not have been a true menstrual period, but rather a sign of early pregnancy. As for fetal growth, slight variations in measurements are common and typically do not indicate any issues, especially if the baby is developing within a healthy range.

If you have further concerns about your pregnancy or any symptoms you are experiencing, it is always best to consult with your healthcare provider for personalized advice and reassurance. Regular prenatal care is crucial for monitoring the health of both you and your baby throughout the pregnancy.

Similar Q&A

Understanding Menstrual Irregularities and Early Pregnancy Signs

Hello doctor, my girlfriend's menstrual period was from February 12 to February 18. We had unprotected intercourse on March 3, and on March 15 and 16, she experienced light bleeding once a day. We thought it was her period, but it stopped after that. On the 17th, she took a ...

Dr. Zhang Kunmin reply Obstetrics and Gynecology
Hello, the questioner: Vaginal bleeding is not always indicative of menstruation; some individuals may mistake early pregnancy bleeding for their period. It is not possible to determine whether one is pregnant based solely on subjective symptoms. Therefore, if you are uncertain w...

Early Signs of Pregnancy: What to Look For Before Your Period

Hello, I apologize for taking up your time, but I have some questions. Since last month, my menstrual cycle has been irregular; it was over two weeks late. I was supposed to start my period on the 7th of this month, but I took traditional Chinese medicine at the end of November t...

Dr. Shi Chengyang reply Obstetrics and Gynecology
Hello Annie: In the early stages of pregnancy, it's important to pay attention to symptoms such as vomiting, chills, fever, and lower abdominal cramping. 1. Severe vomiting may indicate hyperemesis gravidarum. 2. Chills, fever, burning sensation during urination, and diarrhe...

Could Irregular Menstrual Changes Indicate Pregnancy?

Hello Doctor: In the past few months, my menstrual cycle has been about 2-5 days late. This month, I was supposed to start on May 6, but on that day, I noticed what seemed to be the early stages of my period, which was brownish in color. However, it didn't look quite like my...

Dr. Xu Junzheng reply Obstetrics and Gynecology
It is possible that you are pregnant; you should first take a urine test. Thank you!

Am I Pregnant? Understanding Irregular Periods and Pregnancy Signs

Hello, I would like to ask about my menstrual cycle, which has always been irregular and easily affected by external stress. I have a cold constitution. In the past few months, the first days of my menstrual period were on 4/7, 5/18, 6/22, 7/25, no period in August, and 9/12. I a...

Dr. Yang Wangjun reply Obstetrics and Gynecology
Hello: (1) Based on your menstrual dates, your menstrual cycle is relatively regular, although it is on the longer side, occurring approximately every 35 to 45 days. (2) Current pregnancy tests are quite sensitive, and human chorionic gonadotropin (hCG) levels in urine above 25-5...