In the context of research, standardized numerical cutoffs are often applied to verify the diagnosis. The difficulty of diagnosing PMDD is one reason that it can be challenging for lawyers to cite the disorder as a defense of crime, in the very rare cases where PMDD is allegedly associated with criminal violence. DSM-5
The DSM-5 which established seven criteria (A through G) for the diagnosis of PMDD which is paraphrased below. There is overlap between the criteria for PMDD in the DSM-5 and the criteria found in the Daily Record of Severity of Problems (DRSP).According to the DSM-5, a diagnosis of PMDD requires the presence of at least five of these symptoms with one of the symptoms being numbers 1–4. These symptoms should occur during the week before menses and remit after initiation of menses. In order to meet criteria for the diagnosis, the symptoms should be charted prospectively for two consecutive ovulation cycles in order to confirm a temporal and cyclical nature of the symptoms. The symptoms should also be severe enough to affect normal work, school, social activities, and/or relationships with others. The symptoms of Criteria A-C must have been met for most menstrual cycles that occurred in the preceding year, and have to have cause significant impairment in family, work, school, or social functioning. (Criterion D).
However, large cysts can cause hydrocephalus. Genetic causes
There is a possible association between ultrasound-detected fetal CPCs and Trisomy 18. It is not correlated to the presence of Trisomy 21 (Down syndrome). Therefore, genetic counseling is often recommended to provide more information about fetal CPCs, to answer questions and concerns, and to outline available options such as amniocentesis or a blood test from the mother.Generally the risks are very low if there are no other risk factors. If no additional abnormalities are detected by a thorough "level II" ultrasound, the likelihood the fetus has trisomy 18 is very low.A meta-analysis of 8 studies between 1990 and 2000 with choroid plexus cysts that were identified in second-trimester (an incidence of 1.2%). The incidence of the cysts in women younger than 35 was 1% (n=1017). The study found no cases of trisomy 18 in fetuses with cysts whose mother was younger than 35. The study concluded that "there is no evidence that detection of isolated choroid plexus cyst in women who are <35 years of age increases the risk of trisomy 18".Other factors which may have a bearing on the babys chances of developing chromosome problems include:
mothers age at the expected date of delivery
the results of serum screening; XAFP triple testing or quad screening
evidence of other "fetal findings" seen at the time of the ultrasound that may suggest a chromosome problem

References
Further reading
Lun, Melody P.; Monuki, Edwin S.; Lehtinen, Maria K. (2015). "Development and functions of the choroid plexus–cerebrospinal fluid system". Nature Reviews Neuroscience. 16 (8): 445–457. doi:10.1038/nrn3921. PMC 4629451.