Hi, this is something I found on google about irregualr gestational sacs - apparently as long as the contents (yolk sac, fetal pole or baby itself) is normal then you don't have to worry - it may be just the angle at which it was scanned, so everything sounds positive for you.
"There is very little data on gestational sac shape and pregnancy outcome. Remember also, that you are essentially looking at a 3-dimensional structure in only two dimensions. For both reaons, I also think there is no immediate cause for alarm. I reviewed the literature for you and did come across a small but relevant study looking at IVF pregnancies. Abnormal sac shape was not predictive of poor outcome. In addition, you mentioned that the yolk sac and fetal pole were present, so your pregnancy is demonstrating normal sac contents, also positive. Ultimately, the next big milestone would be embryonic cardiac activity, so time will tell for your pregnancy. However, overall based on very limited data, I think your pregnancy is still promising. Please see abstract below, and good luck to you!
J Ultrasound Med. 1992 Jul;11(7):321-5.Links
First trimester findings in pregnancies after in vitro fertilization.Wax MR, Frates M, Benson CB, Yeh J, Doubilet PM.
Department of Radiology, Harvard Medical School, Brigham and Womens Hospital, Boston, Massachusetts.
We assessed the frequency of abnormal sonographic findings and their significance with respect to outcome in pregnancies resulting from in vitro fertilization (IVF). We retrospectively reviewed first trimester sonograms of 53 consecutive IVF patients who had a positive pregnancy test and first trimester ultrasonography at least 4 weeks after embryo transfer, and we correlated the sonographic findings with pregnancy outcome. For controls, we compared the frequency of sonographic abnormalities in these study patients to that in a group of patients who became pregnant after ovulation induction only. In the 53 IVF patients, the numbers of gestational sacs identified on the initial sonogram were as follows: 34 singletons, 11 twins, two triplets, one quadruplets and one quintuplets; no sac was seen in four patients. In 32 patients, the first sonogram was normal, with a visualized yolk sac, or heartbeat, or both. In 10 patients the gestational sac appeared abnormal but sac contents were normal. In seven patients an abnormality of sac contents was identified, including four with an embryo but no heartbeat and three anembryonic sacs. Overall, 40% of IVF patients had sonographic abnormalities, in comparison to 7% in the control group of patients (P less than 0.05, Fishers exact test). Of the 32 patients with normal sonograms, 26 (81%) delivered at least one live infant. Of the 10 patients whose gestation sacs appeared abnormal, nine (90%) gave birth to live infants. Of the seven patients with abnormal sac contents, two (29%) delivered at least one live infant. We conclude that abnormal findings are frequently present on the initial sonogram of pregnant patients after IVF.(ABSTRACT TRUNCATED AT 250 WORDS) "