(concurring in part and dissenting in part, with whom Gants, J., joins; and with whom Marshall, C.J., joins as to parts 1, 3, and 4). The issue at the core of this case is the proper interpretation of the Massachusetts Maternity Leave Act (MMLA), G. L. c. 149, § 105D. The motion judge allowed the defendant attorneys’ motion for summary judgment on the ground that the judgment against Global NAPs, Inc. (Global), as the defendant in the underlying Stephens discrimination case, was based on a correct reading of the MMLA and particularly the interpretative guidelines (MCAD Guidelines) of the Massachusetts Commission Against Discrimination (MCAD). Accordingly, the judge reasoned, if the attorneys on Global’s behalf had filed a timely appeal from that judgment, the Appeals Court would have found no error, and therefore Global suffered no harm as matter of law. This court disagrees, and concludes, based on its reading of the MMLA, that not only were the attorneys not entitled to summary judgment, but Global was. In my view, the court’s interpretation of the MMLA is incomplete and, as applied to this case, incorrect. But I am also of the view *504that the construction adopted by the trial judge in the Stephens case and indorsed by the motion judge here — a construction essentially based on the MCAD Guidelines — was flawed as well. For the reasons I explain, I conclude that both the attorneys’ and Global’s motions for summary judgment should have been denied.
1. As it bears on this case, the MMLA has two essential provisions. The first is in the statute’s first paragraph:
“A female employee who . . . has been employed by the same employer for at least three consecutive months as a full-time employee, who is absent from such employment for a period not exceeding eight weeks for the purpose of giving birth . . . said period to be hereinafter called maternity leave, and who shall give at least two weeks’ notice to her employer of her anticipated date of departure and intention to return, shall be restored to her previous, or a similar, position with the same status, pay, length of service credit and seniority, wherever applicable, as of the date of her leave.”
G. L. c. 149, § 105D, first par. The second is a sentence in the third paragraph:
“Nothing in this section shall be construed to affect any bargaining agreement or company policy which provides for greater or additional benefits than those required under this section.”
Id. at § 105D, third par.
As the court rightly concludes, the first paragraph of the statute clearly limits MMLA benefits — and, of particular relevance here, the retention of the employee’s job at the same pay and status — to no more than eight weeks. Ante at 494. In the court’s view, that is the only protection the statute provides. Ante at 497 (“Once a female employee is absent from employment for more than eight weeks, she is no longer within the purview of the MMLA and, consequently, is not afforded the protections conferred by the statute”).
The court pays lip service to the sentence I have quoted from the statute’s third paragraph (see ante at 498), but appears to read *505it as essentially unconnected to the first paragraph. It is a cardinal rule of statutory construction, however, that no provision in a statute “is to be regarded as superfluous, but each is to be given its ordinary meaning without overemphasizing its effect upon the other terms appearing in the statute, so that the enactment considered as a whole shall constitute a consistent and harmonious statutory provision capable of effectuating the presumed intention of the Legislature.” Commonwealth v. Woods Hole, Martha’s Vineyard & Nantucket S.S. Auth., 352 Mass. 617, 618 (1967), quoting Bolster v. Commissioner of Corps. & Taxation, 319 Mass. 81, 84-85 (1946). See DiFiore v. American Airlines, Inc., 454 Mass. 486, 491 (2009) (“Where possible, we construe the various provisions of a statute in harmony with one another, recognizing that the Legislature did not intend internal contradiction”).
We have in the MMLA both the eight-week limitation on the statutorily required maternity leave in the first paragraph and the Legislature’s express recognition in the third paragraph that employers may provide greater benefits than does the MMLA itself. And, of particular relevance here, this recognition is accompanied by the Legislature’s directive that the statutory limitation in the first paragraph is not to “affect” those more generous benefits. We need to read the provisions of the first paragraph and the third paragraph as working in harmony, if that is possible to do. It is. The third paragraph’s directive, read with the first paragraph’s limitations, means that an employer cannot promise an employee (by policy or, as here, by agreement) a maternity leave of more than eight weeks with a commitment to restore her to her job at the leave’s conclusion and then, when the employee has not returned to work within eight weeks in reliance on the employer’s agreement, interpose the MMLA’s eight-week limitation as the basis for refusing to take the employee back. An employer following such a course is using the statutory limitation as a shield to “affect” — that is, to ignore — its own agreement to offer a longer leave and a job on return, a course of action plainly prohibited by the statute’s third paragraph.1
This interpretation of the MMLA not only gives meaning to *506all its provisions but also advances the explicit legislative directive “that the provisions of c. 15 IB ‘shall be construed liberally’ for the accomplishment of the remedial purposes of the statute.” Dahill v. Police Dep’t of Boston, 434 Mass. 233, 240 (2001), quoting G. L. c. 15IB, § 9.2 See Cormier v. Pezrow New England, Inc., 437 Mass. 302, 304 (2002), quoting Charland v. Muzi Motors, Inc., 417 Mass. 580, 583 (1994), and G. L. c. 151B, § 9 (“One of the principal purposes of G. L. c. 151B is to ‘protect the citizens of the Commonwealth against employment discrimination,’ . . . and its provisions are to be ‘construed liberally for the accomplishment’ of that purpose”). See also Thurdin v. SEI Boston, LLC, 452 Mass. 436, 441 (2008).
2. There is another way of looking at the question of interpretation raised in this case. As indicated, I agree that when an employer contracts to offer maternity leave that exceeds eight weeks, this greater contractual benefit does not automatically become “maternity leave” protected by the MMLA. But where (1) an employer has induced an employee to relinquish her rights under the MMLA by offering her maternity leave greater than eight weeks without informing her that she will lose the protection of the MMLA if she remains on leave beyond eight weeks, (2) the employee relies on this offer by accepting the extended leave, and (3) the employer refuses to reinstate her *507when she seeks to return to her job, the employer is equitably estopped from invoking the time limitation of the MMLA.3
This court and the Appeals Court have recognized the doctrine of equitable estoppel in other settings, although not always finding that it applied in the particular case. See, e.g., Bongaards v. Millen, 440 Mass. 10, 15-16 (2003) (declaratory judgment action concerning trust property; court recognized doctrine of equitable estoppel but found that claim not established); Moran v. Gala, 66 Mass. App. Ct. 135, 139-142 (2006) (plaintiff property owners equitably estopped from asserting claim of adverse possession against neighbor); Harrington v. Fall River Hous. Auth., 27 Mass. App. Ct. 301, 307-310 (1989) (equitable estoppel principles not generally applicable against government, and plaintiffs failed to make out traditional elements of equitable estoppel against defendant housing authority in any event); Cellucci v. Sun Oil Co., 2 Mass. App. Ct. 722, 728-732 (1974), S.C., 368 Mass. 811 (1975) (defendant oil company equitably estopped from denying it had agreed to purchase plaintiff’s property).
Several Federal courts, considering cases brought under the Federal Family and Medical Leave Act (FMLA), 29 U.S.C. §§ 2601 et seq. (2006), have applied principles of equitable estoppel in determining whether the FMLA has been violated in somewhat analogous circumstances, that is, where an employee has relied on information his or her employer provided relating to entitlement to FMLA leave, has taken the leave, and then is terminated for having done so because, it turns out, the information provided was incorrect. See, e.g., Minard v. IYC Deltacom Communications, Inc., 447 F.3d 352, 358-359 (5th Cir. 2006); Duty v. Norton-Alcoa Proppants, 293 F.3d 481, 493-494 (8th Cir. 2002), and cases cited. See also Kosakow v. New Rochelle Radiology Assocs., 274 F.3d 706, 724-725 (2d Cir. 2001). We have often applied Federal case law interpreting cognate Federal antidiscrimination statutes when looking to interpret G. L. c. 151B. See, e.g., Wheatley v. American Tel. & Tel. Co., 418 Mass. 394, 397 (1994). The MMLA and the FMLA are cognate statutes with ties to antidiscrimination laws, and we should fol*508low the Federal courts in their application of equitable estoppel principles here because the approach appropriately serves to protect the interests of those for whose benefit the statutes most certainly were enacted, namely, employees.
The remedy in contract that the court contends would be available to an employee who is not reinstated is, in practice, largely illusory and, where it is not an illusion, far weaker than the remedy available under the MMLA. It is illusory because, while the MMLA expressly provides that a female employee returning from maternity leave “shall be restored to her previous, or a similar, position with the same status, pay, length of service credit and seniority ... as of the date of her leave,” G. L. c. 149, § 105D, the “contract” whereby an employer grants additional maternity leave may be far more ambiguous as to what is promised. It is weaker because, while an employee who prevails on a MMLA claim is entitled to an award of her attorney’s fees and costs, and the possibility of punitive damages, G. L. c. 151B, §§ 4 (11 A), 9, an employee with a remedy only in contract is entitled to compensatory damages alone.
3. While I thus conclude that the court’s construction of the MMLA is overly narrow, I agree that the MCAD Guidelines cannot serve as “the source of a remedy for Stephens’s termination from employment.” Ante at 497. The MCAD Guidelines represent policies adopted pursuant to G. L. c. 15IB, § 2. The Legislature has given the MCAD separate statutory authority to promulgate regulations. G. L. c. 151B, § 3 (5). This court gives deference to MCAD Guidelines when we are called on to interpret a particular term or phrase in c. 151B. See, e.g., Modern Cont./Obayashi v. Massachusetts Comm’n Against Discrimination, 445 Mass. 96, 106 (2005); Dahill v. Police Dep’t of Boston, 434 Mass, at 239-240. However, the guidelines are not formal regulations duly promulgated pursuant to G. L. c. 151B, § 3 (5). See G. L. c. 30A, § 2. Accordingly, they do not set “requirement[s] of general application and future effect,” G. L. c. 30A, § 1, that carry the force of law. Contrast Solomon v. School Comm. of Boston, 395 Mass. 12, 16 (1985). Contrast also Ocean Spray Cranberries, Inc. v. Massachusetts Comm’n Against Discrimination, 441 Mass. 632, 641-642 (2004). As a result, the MCAD Guidelines cannot create and impose on employers an affirmative notice obligation *509that the MMLA itself does not mention. Cf. Water Dep’t of Fairhaven v. Department of Envtl. Protection, 455 Mass. 740, 749 (2010).4
In this case, the motion judge stated that the trial judge in the Stephens litigation had been correct in “pointing to the MCAD guideline[s].” In effect, the motion judge was agreeing with the trial judge that the MCAD Guidelines imposed on Global an affirmative obligation to notify Stephens that she would not be entitled to full MMLA benefits (including the return to her job) if she took the ten weeks of maternity leave that Global offered, rather than the statutory eight — with the direct consequence of *510being liable in damages for violation of the MMLA if the notice was not provided.5 Because the MCAD Guidelines cannot bear the weight that the judges below placed on them, the motion judge’s allowance of the attorneys’ motions for summary judgment was in error.
4. That the attorneys were not entitled to summary judgment in this case does not necessarily mean that Global’s motion for partial summary judgment should have been granted. I agree with the court that the record establishes the attorneys’ negligence in failing to file a timely notice of appeal. I do not agree, however, that Global has proved the attorneys’ negligence was a proximate cause of its loss as matter of law. Ante at 501. The complaint in the Stephens litigation sets out a claim for violation of the MMLA itself and does not mention the MCAD Guidelines. The trial transcripts from that litigation that are included in the record before us reflect a significant amount of evidence supporting a claim that Global had violated the MMLA in precisely the manner I have described above. In the circumstances, had Global been able to pursue its appeal, the Appeals Court could have decided to reverse the judgment because of the erroneous jury instructions based on the MCAD Guidelines, but to remand the case to the Superior Court for a new trial with proper instructions. In that event, to prevail in its malpractice case against the attorneys, Global would be required to establish that it would have prevailed in such a retrial. See 4 R.E. Mallen & J.M. Smith, Legal Malpractice § 31:52, at 748, 756-757 (2010) (“Initially, the client must prove that, but for the attorney’s negligence, *511[the client] should have prevailed on the . . . appeal”; “[i]f the appeal should have been successful, the [client] must next prove there should have been a better result. ... If a retrial is the result of appellate review, then the client must next persuade the trier of fact that the client should have done better at the new trial”). The parties have not addressed these issues in the present appeal, and it may be that the record presently before the court is not sufficient to do so. I would reverse the judgment of the Superior Court and remand for further proceedings.
Global NAPs, Inc. (Global), argues that the language in the third paragraph *506of the Massachusetts Maternity Leave Act (MMLA), G. L. c. 149, § 105D, concerning “greater or additional benefits” means that “if employers offer greater benefits, such benefits ‘shall not be affected’ by any provision of the MMLA,” but are rather matters of private contract only. Global has rephrased the statute in making this argument. I agree with Global’s general point that where an employer contracts to offer a maternity leave that exceeds eight weeks, this greater contractual benefit does not automatically become “maternity leave” protected by the MMLA. But I read the statutory language actually used by the Legislature in the MMLA’s third paragraph (“Nothing in this section shall be construed to affect any bargaining agreement or company policy which provides for greater or additional benefits than those required under this section”) as reflecting a legislative desire to prevent an employer from using the MMLA as a means to extricate itself from its own more generous contractual commitments.
As the court recognizes, G. L. c. 151B comes into play because the Legislature has defined as an “unlawful practice” under G. L. c. 151B, § 4, an employer’s refusal to restore an employee to employment following a maternity leave taken under the MMLA, or failure otherwise to comply with the MMLA. G. L. c. 151B, § 4 (11 A).
The language in the third paragraph of the MMLA that I discuss in part 1, supra, represents, in effect, a statutory expression of estoppel; I address here the separate doctrine of equitable estoppel.
The notice requirement in the interpretive guidelines of the Massachusetts Commission Against Discrimination (MCAD) (“If the employer does not intend for full MMLA rights to apply to the period beyond eight weeks, however, it must clearly so inform the employee in writing prior to the commencement of the leave”) appears to be designed to harmonize the two separate provisions in the first and third paragraphs of the MMLA that I have discussed in part 1, supra. The policy embedded in the guidelines does not obligate an employer to increase the amount of time to which MMLA rights apply, nor does it impose any automatic, preset penalty if the employer does not provide the prescribed notice. Contrast Ragsdale v. Wolverine World Wide, Inc., 535 U.S. 81, 88-89, 90-91 (2002) (Federal regulation implementing Family and Medical Leave Act [FMLA], and requiring employers who fail to provide notice that employer-provided leave counts against FMLA entitlement to grant employees twelve additional weeks of FMLA leave, regardless of prejudice to employee, held invalid because it altered FMLA’s remedial structure by removing requirement that employee prove impairment of rights and prejudice). By directing employers who may provide maternity leave that exceeds eight weeks to notify their employees that the MMLA rights will end at the eight-week mark, the MCAD policy has reciprocal benefits for employees and employers: it protects employees from losing their MMLA rights through uninformed reliance on an employer’s offer of a maternity leave longer than eight weeks; and it provides employers who give the notice a safe harbor against employee claims of MMLA violation where the employee does not return to work at the end of eight weeks. While the MCAD cannot establish such a notice requirement by adopting guidelines, it may well have the authority to do so through a duly promulgated regulation, and I do not understand the court to hold otherwise. See Water Dep’t of Fairhaven v. Department of Envtl. Protection, 455 Mass. 740, 749-751 (2010) (discussing authority of Department of Environmental Protection to adopt, by regulation, mandatory conservation measures as “registration conditions” on cities and towns and to create adjudicatory proceeding for registrants, although department lacked power to do either without enacting regulations). This court has recognized the broad power granted by G. L. c. 151B, § 3 (5), to the MCAD to adopt regulations designed to carry out the provisions of c. 15 IB. See, e.g., Ocean Spray Cranberries, Inc. v. Massachusetts Comm’n Against Discrimination, 441 Mass. 632, 641-642 (2004).
That this was the trial judge’s position is made crystal clear from his instructions to the jury. The judge told the jury that Stephens’s claim was that Global had violated the MMLA, and that violations of the MMLA are “deemed unfair employment practices in violation of the prohibition on gender discrimination in accordance with [G. L. c. 15IB].” He then explained the provisions of the MMLA, stating, in relevant part, “An employer may grant a longer maternity leave than required under the [MMLA], however, if the employer does not intend to give the employee full [MMLA] rights at the end of a leave longer than eight weeks, the employer must clearly so inform the employee in writing prior to the beginning of the leave." The instruction did not mention the MCAD Guidelines but, as the portion just quoted reflects, directly incorporated the notice requirement contained in the guidelines into the MMLA itself, making them an integral part of the statute that Stephens claimed Global had violated. The trial judge reiterated the same view in his decision on Global’s motion for judgment notwithstanding the verdict.